Question

In the polynomial below, what number should replace the question mark to produce a difference of squares?

x2 + ?x - 25
A. 25
B. 5
C. 0
D. 10

Answer 1

hint \(a^2-b^2 = (a-b)(a+b)\)

Answer 2

\(x^2-25=x^2-5^2=(x-5)(x+5)\)

Answer 3

so what is the middle term?

Answer 4

5?

Answer 5

\(x^2+\color{blue}{b}x-25=x^2-25\)

what does \(\color{blue}{b}\) have to be for this to be true?

Answer 6

0

Answer 7

ahh, Thank you so much!