The equation is true for all , where a and d are integers. What is the value of ?
A
B
C
D
Correct answer: C
Explanation
Choice C is correct. Since the expression can be factored as , the given equation can be rewritten as . Since , is also not equal to 0, so both the numerator and denominator of can be divided by . This gives . Equating the coefficient of x on each side of the equation gives . Equating the constant terms gives . The sum is .
Choice A is incorrect and may result from incorrectly simplifying the equation. Choices B and D are incorrect. They are the values of d and a, respectively, not .