Question

Which of the binomials below is a factor of this expression?

64A2 - 81B2

Answer 1

B

Explanation:

This is the difference of perfect squares, which follows a pattern of

(A+B)(A-B)

We have 64, which is 8-squared,

we have A squared, which is A squared ( :/ )

we have 81, which is 9-squared, and

we have B-squared, which is B squared.

We can factor this then following the pattern into:

(8A+9B)(8A-9B)

Choice B only matches one of our binomials.

Answer 2

B. 8A + 9B.

Explanation:

The general form is

a^2 - b^2 = (a - b)(a + b) so here we have:

a = square root of 64A^2 = 8A and b = square root of 81B^2 = 9B and therefore:

64A^2 - 81B^2

= (8A - 9B)(8A + 9B).