2007-05-07 08:48:36 · 14 answers · asked by girlsrule688 1 in Science & Mathematics ➔ Mathematics
x^2 - 9
2007-05-07 08:51:26 · answer #1 · answered by Britt L 2 · 1⤊ 0⤋
The rule is first, outer, inner, last : first: x times x = x2
outer: -3 times x = -3x
inner: 3 times x = 3x
last : 3 times -3 = -9
add together = x2+3x+(-3x) -9 = x2-9
2007-05-07 15:53:42 · answer #2 · answered by CHRISTOPHER C 4 · 0⤊ 0⤋
this is similar to multiplying by x(x-3) just with another number 3.. so,
using distributive property, forget foil..it only works for binomial with binomial, and distributive works for any combination.
so here
x(x-3) + 3(x-3)
x^2-3x +3x-9
simplifying,
x^2 -9
2007-05-07 16:00:29 · answer #3 · answered by JAC 3 · 0⤊ 0⤋
x^2 - 9
2007-05-07 15:51:48 · answer #4 · answered by ulfsnilsson 2 · 1⤊ 0⤋
x^2-9
2007-05-07 16:53:27 · answer #5 · answered by Anonymous · 0⤊ 0⤋
This is a very common problem. If you can not do it you are in big trouble. You must be able to reverse the process in factoring. Note how x^1 cancel out. The other numbers are ^2.
2007-05-07 16:03:06 · answer #6 · answered by Richard F 7 · 0⤊ 0⤋
x^2-9
2007-05-07 15:52:33 · answer #7 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋
FOIL( first, outer, inner, last)
(x+3)(x-3)
F: x times x = x2
O: x times -3 = -3x
I: 3 times x = 3x
L: 3 times -3 = -9
then when you get that, you have to add O & I. therefore
-3x plus 3x =0
thus you are left with x2 and -9 only.
so your answer would be: x2 -9
good luck with math. practice makes perfect. a good teach who knows how to explain would also be helpful.. LOL
2007-05-07 15:59:50 · answer #8 · answered by annlyvqp 3 · 0⤊ 0⤋
Use the F.O.I.L. method (First, Outside, Inside, last)
x^2 -3x +3x - 9
x^2 - 9
2007-05-07 15:52:21 · answer #9 · answered by Anonymous · 0⤊ 0⤋
x²-9
You use FOILing (First, Outside, Inside, Last)
(x+3)(x-3)
x(x)+x(-3)+3(x)+3(-3)
I hope I explained it well enough!
2007-05-07 15:56:23 · answer #10 · answered by sheritta n 2 · 0⤊ 0⤋