{"id":"cb_practice_pdf:t11-math-m1-q21","source_id":"cb_practice_pdf","source_item_id":"t11-math-m1-q21","external_id":null,"ibn":null,"question_id":null,"program":"SAT","module":"math","domain_code":null,"domain":null,"skill_code":null,"skill":null,"difficulty":null,"score_band":null,"answer_type":"spr","answer_source":"rationale","layout_warning":null,"form_id":"cb_practice_pdf:test-11","module_number":1,"position":21,"stem":"21 + + = x^2 7x 5 0 One solution to the given equation can be written as -7 k = x (+)/2, where k is a constant. What is the value of k?","stimulus":"","stimulus_html":null,"stem_html":"<p>21 + + = x^2 7x 5 0 One solution to the given equation can be written as -7 k = x (+)/2, where k is a constant. What is the value of k?</p>","rationale_html":"<p>29 The correct answer is . The solutions to a quadratic equation in the form 2+ + =0 ax bx c , where a, b, and c are constants, can be calculated using the - + 2-4 = b b ac quadratic formula, which gives two solutions: x 2 and = - b - b 2-4 ac 2+ a + =0 = x 2 . The given equation is in the form ax bx c , where a 1, a = = b 7, and c 5. It follows that one solution to the given quadratic equation is -7+ 72-4 1 5 -7+ 49-20 -7+ 29 x = 2 1 ] g] g , or x = 2 , which is equivalent to x = 2 . It’s ] g -7+ = k given that one solution to the given equation can be written as x 2 , where 29 k is a constant. It follows that the value of k is .</p>","correct_answer":["29"],"has_media":false,"has_mathml":false,"has_table":false,"source_created_at":null,"source_updated_at":null,"options":[],"attribution":{"source_id":"cb_practice_pdf","source_name":"College Board full-length SAT practice tests (PDF)","rights_holder":"College Board","canonical_url":"https://satsuite.collegeboard.org/practice/practice-tests/paper","retrieved_from":"https://satsuite.collegeboard.org/practice/practice-tests/paper","attribution":"Full-length SAT practice tests 4–11 © College Board, published free at satsuite.collegeboard.org.","disclaimer":"Extracted from PDF layout: equations, figures and tables do not survive intact. Use the original PDFs for anything the text renders poorly. SAT® is a trademark registered by the College Board, which is not affiliated with and does not endorse this project.","license":"College Board copyright. Free to download; not licensed for redistribution.","redistributable":false,"item_count":905}}