Question

If for all real values of x, (x + c)(x + 4) = x2 + 8x + 4c, then c = ?

A. 2
B. 4
C. 6
D. 8
E. 10

Answer 1

B. 4

Explanation:

When you perform the multiplication, you get ...

(x +c)(x +4) = x² + (c+4)x +4c = x² + 8x +4c

Then ...

c + 4 = 8 . . . . coefficients of x must match

c = 4 . . . . . matches choice B