2007-08-11 09:15:35 · 5 answers · asked by Meghan M 1 in Science & Mathematics ➔ Mathematics
First: x*x = x^2
Outside: x * 8 = 8x
Inside: -9 * x = -9x
Last: -9 * 8 = -72
Add'em all up:
x^2 - x - 72
2007-08-11 09:19:16 · answer #1 · answered by MathProf 4 · 1⤊ 0⤋
an easy way
( x + a )( x + b ) = x^2 + ( a + b )*x + a*b
example :
( x - 9 )( x + 8 ) = x^2 + ( -9 + 8 )x + -9*8
= x^2 -x -72
2007-08-11 16:25:00 · answer #2 · answered by ali k 1 · 0⤊ 0⤋
x^2 -x-72
2007-08-11 16:23:53 · answer #3 · answered by :D 3 · 0⤊ 0⤋
x^2 -x-72
2007-08-11 16:20:58 · answer #4 · answered by samir s 1 · 0⤊ 0⤋
(x - 9)(x + 8) =
x² + 8x - 9x - 72
Collect like terms
x² - x - 72
- - - - - - -
F = x²
O = 8x
I = - 9x
L = - 72
- - - - - - -s-
2007-08-11 16:38:18 · answer #5 · answered by SAMUEL D 7 · 0⤊ 0⤋