Question

Does each of the following result in
X^2– 100?
A (x-90) + (x - 10)
B (x - 9)^2 – 19
C x(x – 100)
D (x + 10)(x - 10)

Answer 1

Answer :
D - (x+10)(x-10)


Solution:
x^2 -100
= x^2 - 10^2
= (x+10)(x-10) { a^2 -b^2 = (a+b)(a-b)