Question

What is a simpler form of the following expressions?

(7p – 8)(7p + 8) (1 point)
49p2 + 112p + 64
49p2 – 112p – 64
49p2 + 64
49p2 – 64

Answer 1

the last one

Answer 2

Remember FOIL, First, Outside, Inside, Last.
\[(7p-8)(7p+8)\]
First
\[7p*7p = 49p^{2}\]
Outside
\[7p*8 = 56p\]
Inside
\[-8*7p = -56p\]
Last
\[-8*8 = -64\]
Add all these up
\[49p^{2}+56p-56p-64 = 49p^{2}-64\]
This also helps where if you have the form
\[(Ax+b)(Ax-b) = A^{2}x^{2} - b^{2}\]