Question

When asked to factor the x^2 - 144, a student gives the answer (x - 12)(x - 12). What is wrong with this answer?

A. Both minus signs should be plus signs l

B. One of the minus signs should be a plus sign

C. There is nothing wrong with this answer

D. -1 is also a factor

Answer 1

B

Explanation:

because in general

(a + b)(a - b) = a² - b²

when the second term is negative, it has to be the product of a positive and a negative number.

positive × positive = positive

negative × negative = positive