Question

What number is represented by the letter in the identity below:

x2+2x−35=(x+7)(x−a)

Answer 1

a = 5

Explanation:

Given

x² + 2x - 35

Consider the factors of the constant term (- 35) which sum to give the coefficient of the x- term (+ 2)

The factors are + 7 and - 5, since

7 × - 5 = - 35 and 7 - 5 = + 2, thus

x² + 2x - 35 = (x + 7)(x - 5)

Compare to (x + 7)(x - a)

with a = 5