(a+9)(a-2) thanks, I need some help on algebra
2007-06-01 17:32:34 · 10 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
First, let's define FOIL.
First = a and a
Outside = a and -2
Inisde = 9 and a
Last = 9 and -2
Then let's multiply the numbers that are grouped together.
a^2 - 2a + 9a -18
Next, add the product of the outside and inside numbers.
a^2 + 7a -18
So the answer is a^2 + 7a - 18...
2007-06-01 17:53:52 · answer #1 · answered by whitey-chan 3 · 0⤊ 0⤋
Foil=first outside inside last. However this is a very foolish way to teach math. Your teacher should be scolded for ever teaching you this word. The reason for this is because learning FOIL teaches you the "steps" to get the right answer letting you completely ignore learning the mathematics that is truly behind the scene.
There is an axioms called "the distributive axiom" or property that is working behind the scenes here. The distributive axiom states: a(b+c)=ab+ac. This property can help us multiply out (a+9)(a-2) = (a+9)a+(a+9)(-2). Here we used the distributive property because (a-2) is the same as (a+-2).
Then using the distributive property again (a+9)a+(a+9)(-2) = a^2+9a+-2a-18.
2007-06-02 07:05:16 · answer #2 · answered by Stochastic 2 · 0⤊ 0⤋
a^2-2a+9a-18
a^2+7a-18 ANSWER
9-2=7 PROOFREAD
You can proofread an FOIL product or polynominal by seeing if the problems' last number and its two numbers that go into it, matches the middle number when added together.
2007-06-01 18:45:20 · answer #3 · answered by Kandice F 4 · 0⤊ 0⤋
Multiply by a and then by 9:-
a² - 2a + 9a - 18
a² + 7a - 18
2007-06-02 07:38:56 · answer #4 · answered by Como 7 · 0⤊ 0⤋
(a+9)(a-2)
= a^2 - 2a + 9a - 18
= a^2 + 7a - 18
2007-06-01 17:38:09 · answer #5 · answered by Kemmy 6 · 0⤊ 0⤋
FOiL = First Outter Inner Last.
so it's a * a ..
then a *-2
then 9 * a
then 9*-2 i believe.
then you combine like terms. and there's youranswer!
2007-06-01 18:17:06 · answer #6 · answered by my_only_onee_x3 2 · 0⤊ 0⤋
FIRST: a * a
OUTSIDE: a * (-2)
INSIDE: 9 * a
LAST: 9 * (-2)
a^2-2a+9a-18 = a^2+7a-18
GOOD LUCK
2007-06-01 17:37:30 · answer #7 · answered by goldenret35 2 · 1⤊ 0⤋
asquared-2a+9a-18
a^2+7a-18
distribute each number/letter to the others
2007-06-01 17:40:46 · answer #8 · answered by mai 2 · 0⤊ 0⤋
the sole foil I definitely have interior the home is reynold's wrap. For this question tho, i could say.....in simple terms multiply it out. it is not that onerous....is it? it is in simple terms arithmetic. (a+b)(c+d)=ac+advert+bc+bd
2016-12-12 08:57:20 · answer #9 · answered by ? 4 · 0⤊ 0⤋
(a)(a)+(a)(-2)+(9)(a)+(9)(-2)
=a²-2a+9a-18
=a²-7a-18
2007-06-01 17:48:13 · answer #10 · answered by sharaont 6 · 0⤊ 0⤋