{"id":"cb_question_bank:2dced346-b788-4d86-a8fb-ce069b5bc569","source_id":"cb_question_bank","source_item_id":"2dced346-b788-4d86-a8fb-ce069b5bc569","external_id":"2ae9a93c-e2a5-4e1e-9012-cdaf6592e09a","ibn":null,"question_id":"841ef26c","program":"SAT","module":"math","domain_code":"P","domain":"Advanced Math","skill_code":"P.C.","skill":"Nonlinear functions","difficulty":"H","score_band":7,"answer_type":"mcq","answer_source":"key","layout_warning":null,"form_id":null,"module_number":null,"position":null,"stem":"f left parenthesis x right parenthesis equals 4 x squared plus 64 x plus 262 The function g is defined by g left parenthesis x right parenthesis equals f left parenthesis x plus 5 right parenthesis . For what value of x does g left parenthesis x right parenthesis reach its minimum?","stimulus":"","stimulus_html":null,"stem_html":"<p style=\"text-align: center;\"><math alttext=\"f left parenthesis x right parenthesis equals 4 x squared plus 64 x plus 262\"><mi>f</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mrow>\n\t<mrow>\n\t\t<mn>4</mn>\n\t\t<msup>\n\t\t\t<mi>x</mi>\n\t\t\t<mn>2</mn>\n\t\t</msup>\n\t</mrow>\n\t<mo>+</mo>\n\t<mrow>\n\t\t<mn>64</mn>\n\t\t<mi>x</mi>\n\t</mrow>\n\t<mo>+</mo>\n\t<mn>262</mn>\n</mrow>\n</math></p>\n<p style=\"text-align: left;\">The function <math alttext=\"g\"><mi>g</mi>\n</math> is defined by <math alttext=\"g left parenthesis x right parenthesis equals f left parenthesis x plus 5 right parenthesis\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mi>f</mi><mfenced><mrow><mi>x</mi><mo>+</mo><mrow><mn>5</mn></mrow></mrow></mfenced></math>. For what value of <math alttext=\"x\"><mi>x</mi>\n</math> does <math alttext=\"g left parenthesis x right parenthesis\"><mi>g</mi><mfenced><mi>x</mi></mfenced></math> reach its minimum?</p>","rationale_html":"<p style=\"text-align: left;\">Choice A is correct. It's given that&nbsp;<math alttext=\"g left parenthesis x right parenthesis equals f left parenthesis x plus 5 right parenthesis\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mi>f</mi><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced></math>. Since&nbsp;<math alttext=\"f left parenthesis x right parenthesis equals 4 x squared plus 64 x plus 262\"><mi>f</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mn>4</mn><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><mn>64</mn><mi>x</mi><mo>+</mo><mn>262</mn></math>, it follows that <math alttext=\"f left parenthesis x plus 5 right parenthesis equals 4 left parenthesis x plus 5 right parenthesis squared plus 64 left parenthesis x plus 5 right parenthesis plus 262\"><mi>f</mi><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced><mo>=</mo><mn>4</mn><msup><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced><mn>2</mn></msup><mo>+</mo><mn>64</mn><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced><mo>+</mo><mn>262</mn></math>. Expanding the quantity&nbsp;<math alttext=\"left parenthesis x plus 5 right parenthesis squared\"><msup><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced><mn>2</mn></msup></math> in this equation yields <math alttext=\"f left parenthesis x plus 5 right parenthesis equals 4 left parenthesis x squared plus 10 x plus 25 right parenthesis plus 64 left parenthesis x plus 5 right parenthesis plus 262\"><mi>f</mi><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced><mo>=</mo><mn>4</mn><mfenced><mrow><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><mn>10</mn><mi>x</mi><mo>+</mo><mn>25</mn></mrow></mfenced><mo>+</mo><mn>64</mn><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced><mo>+</mo><mn>262</mn></math>. Distributing the <math alttext=\"4\"><mn>4</mn>\n</math> and the <math alttext=\"64\"><mn>64</mn>\n</math> yields&nbsp;<math alttext=\"f left parenthesis x plus 5 right parenthesis equals 4 x squared plus 40 x plus 100 plus 64 x plus 320 plus 262\"><mi>f</mi><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced><mo>=</mo><mn>4</mn><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><mn>40</mn><mi>x</mi><mo>+</mo><mn>100</mn><mo>+</mo><mn>64</mn><mi>x</mi><mo>+</mo><mn>320</mn><mo>+</mo><mn>262</mn></math>. Combining like terms yields&nbsp;<math alttext=\"f left parenthesis x plus 5 right parenthesis equals 4 x squared plus 104 x plus 682\"><mi>f</mi><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced><mo>=</mo><mn>4</mn><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><mn>104</mn><mi>x</mi><mo>+</mo><mn>682</mn></math>. Therefore, <math alttext=\"g left parenthesis x right parenthesis equals 4 x squared plus 104 x plus 682\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mn>4</mn><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><mn>104</mn><mi>x</mi><mo>+</mo><mn>682</mn></math>. For a quadratic function defined by an equation of the form&nbsp;<math alttext=\"g left parenthesis x right parenthesis equals a left parenthesis x minus h right parenthesis squared plus k\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mi>a</mi><msup><mfenced><mrow><mi>x</mi><mo>-</mo><mi>h</mi></mrow></mfenced><mn>2</mn></msup><mo>+</mo><mi>k</mi></math>, where <math alttext=\"a\"><mi>a</mi>\n</math>, <math alttext=\"h\"><mi>h</mi>\n</math>, and <math alttext=\"k\"><mi>k</mi>\n</math> are constants and <math alttext=\"a\"><mi>a</mi>\n</math> is positive,&nbsp;<math alttext=\"g left parenthesis x right parenthesis\"><mi>g</mi><mfenced><mi>x</mi></mfenced></math> reaches its minimum, <math alttext=\"k\"><mi>k</mi>\n</math>, when the value of <math alttext=\"x\"><mi>x</mi>\n</math> is <math alttext=\"h\"><mi>h</mi>\n</math>. The equation&nbsp;<math alttext=\"g left parenthesis x right parenthesis equals 4 x squared plus 104 x plus 682\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mn>4</mn><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><mn>104</mn><mi>x</mi><mo>+</mo><mn>682</mn></math> can be rewritten in this form by completing the square. This equation is equivalent to&nbsp;<math alttext=\"g left parenthesis x right parenthesis equals 4 left parenthesis x squared plus 26 right parenthesis plus 682\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mn>4</mn><mfenced><mrow><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><mn>26</mn></mrow></mfenced><mo>+</mo><mn>682</mn></math>, or&nbsp;<math alttext=\"g left parenthesis x right parenthesis equals 4 left parenthesis x squared plus 26 x plus 169 minus 169 right parenthesis plus 682\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mn>4</mn><mfenced><mrow><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><mn>26</mn><mi>x</mi><mo>+</mo><mn>169</mn><mo>-</mo><mn>169</mn></mrow></mfenced><mo>+</mo><mn>682</mn></math>. This equation can be rewritten as&nbsp;<math alttext=\"g left parenthesis x right parenthesis equals 4 left parenthesis left parenthesis x plus 13 right parenthesis squared minus 169 right parenthesis plus 682\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mn>4</mn><mfenced><mrow><msup><mfenced><mrow><mi>x</mi><mo>+</mo><mn>13</mn></mrow></mfenced><mn>2</mn></msup><mo>-</mo><mn>169</mn></mrow></mfenced><mo>+</mo><mn>682</mn></math>, or&nbsp;<math alttext=\"g left parenthesis x right parenthesis equals 4 left parenthesis x plus 13 right parenthesis squared minus 4 left parenthesis 169 right parenthesis plus 682\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mn>4</mn><msup><mfenced><mrow><mi>x</mi><mo>+</mo><mn>13</mn></mrow></mfenced><mn>2</mn></msup><mo>-</mo><mn>4</mn><mfenced><mn>169</mn></mfenced><mo>+</mo><mn>682</mn></math>, which is equivalent to&nbsp;<math alttext=\"g left parenthesis x right parenthesis equals 4 left parenthesis x plus 13 right parenthesis squared plus 6\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mn>4</mn><msup><mfenced><mrow><mi>x</mi><mo>+</mo><mn>13</mn></mrow></mfenced><mn>2</mn></msup><mo>+</mo><mn>6</mn></math>. This equation is in the form&nbsp;<math alttext=\"g left parenthesis x right parenthesis equals a left parenthesis x minus h right parenthesis squared plus k\"><mi>g</mi><mfenced><mi>x</mi></mfenced><mo>=</mo><mi>a</mi><msup><mfenced><mrow><mi>x</mi><mo>-</mo><mi>h</mi></mrow></mfenced><mn>2</mn></msup><mo>+</mo><mi>k</mi></math>, where <math alttext=\"a equals 4\"><mrow>\n\t<mi>a</mi>\n\t<mo>=</mo>\n\t<mn>4</mn>\n</mrow>\n</math>, <math alttext=\"h equals negative 13\"><mrow>\n\t<mi>h</mi>\n\t<mo>=</mo>\n\t<mo>-</mo><mn>13</mn>\n</mrow>\n</math>, and <math alttext=\"k equals 6\"><mrow>\n\t<mi>k</mi>\n\t<mo>=</mo>\n\t<mn>6</mn>\n</mrow>\n</math>. Therefore,&nbsp;<math alttext=\"g left parenthesis x right parenthesis\"><mi>g</mi><mfenced><mi>x</mi></mfenced></math> reaches its minimum when the value of <math alttext=\"x\"><mi>x</mi>\n</math> is <math alttext=\"negative 13\"><mo>-</mo><mn>13</mn>\n</math>.</p>\n<p style=\"text-align: left;\">Choice B is incorrect. This is the value of <math alttext=\"x\"><mi>x</mi>\n</math> for which <math alttext=\"f left parenthesis x right parenthesis\"><mi>f</mi><mfenced><mi>x</mi></mfenced></math>, rather than&nbsp;<math alttext=\"g left parenthesis x right parenthesis\"><mi>g</mi><mfenced><mi>x</mi></mfenced></math>, reaches its minimum.</p>\n<p style=\"text-align: left;\">Choice C is incorrect and may result from conceptual or calculation errors.</p>\n<p style=\"text-align: left;\">Choice D is incorrect. This is the value of <math alttext=\"x\"><mi>x</mi>\n</math> for which&nbsp;<math alttext=\"f left parenthesis x minus 5 right parenthesis\"><mi>f</mi><mfenced><mrow><mi>x</mi><mo>-</mo><mn>5</mn></mrow></mfenced></math>, rather than&nbsp;<math alttext=\"f left parenthesis x plus 5 right parenthesis\"><mi>f</mi><mfenced><mrow><mi>x</mi><mo>+</mo><mn>5</mn></mrow></mfenced></math>, reaches its minimum.</p>","correct_answer":["A"],"has_media":false,"has_mathml":true,"has_table":false,"source_created_at":"2023-08-02T20:25:59.828000+00:00","source_updated_at":"2023-08-02T20:25:59.828000+00:00","options":[{"label":"A","content_html":"<p><math alttext=\"negative 13\"><mo>-</mo><mn>13</mn>\n</math></p>","ord":0},{"label":"B","content_html":"<p><math alttext=\"negative 8\"><mo>-</mo><mn>8</mn>\n</math></p>","ord":1},{"label":"C","content_html":"<p><math alttext=\"negative 5\"><mo>-</mo><mn>5</mn>\n</math></p>","ord":2},{"label":"D","content_html":"<p><math alttext=\"negative 3\"><mo>-</mo><mn>3</mn>\n</math></p>","ord":3}],"attribution":{"source_id":"cb_question_bank","source_name":"College Board digital SAT question bank (community dump)","rights_holder":"College Board","canonical_url":"https://satsuitequestionbank.collegeboard.org/","retrieved_from":"https://raw.githubusercontent.com/mdn522/sat-question-bank/main/data/cb-digital-questions.json","attribution":"SAT practice questions © College Board, from the official SAT Suite Question Bank. Retrieved via the community dump at github.com/mdn522/sat-question-bank.","disclaimer":"SAT® and PSAT/NMSQT® are trademarks registered by the College Board, which is not affiliated with, does not sponsor, and does not endorse this project.","license":"College Board copyright; source repository carries no licence. Local use only.","redistributable":false,"item_count":2017}}