Question

Which of the following is equivalent to 121 − x2 ?

(11 − x)^2
(11 − x)x
(11 − x)(11 − x)
(11 − x)(11 + x)
(121 + x)(1 − x)

Answer 1

Multiply these two binomials together:

(a+b)(a-b)

Answer 2

what you have here is a difference of 2 squares...

http://www.regentsprep.org/regents/math/algebra/av6/Lfactps.htm

Answer 3

The difference of perfect squares a^2 - b, if a and b are perfect squares, is (a + b)(a - b)

Answer 4

Always.

Answer 5

a = 11 and b = x, these are found by finding the square roots of 121 and x^2

Answer 6

Hence, the name difference of perfect squares.