Question

What is a simpler form of the following expressions?

(j + 7)(j – 7)

Answer 1

FOIL

Answer 2

It's a difference of two squares: \[a^2 - b^2 = (a + b) (a-b)\]

Answer 3

@ChanHamm Uh, no.
\[(j+7)(j-7) = j(j-7) + 7(j-z) = j^2 -7j + 7j -49 = j^2 - 49\]