Mathematics
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OpenStudy (anonymous):
Does 5a³+15a²-6a-18 factor to (5a²-6)(a+3)?
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OpenStudy (anonymous):
A good way to check is to foil out and compare.
OpenStudy (anonymous):
I dont think i foil right
Directrix (directrix):
5a³+15a²-6a-18 = 5a² ( a + 3) - 6 ( a + 3) = (a + 3) ( 5a² - 6).
Check the accuracy of this factoring by grouping.
Directrix (directrix):
FOIL -> First, Outer, Inner, Last
(5a²-6)(a+3)
Directrix (directrix):
First terms are those that appear first in each set of parentheses.
5a² and a. So what is 5a² times a?
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Directrix (directrix):
5a² times a ? @JaneDoe100
OpenStudy (anonymous):
sorry i was making a factoring darwing
Directrix (directrix):
We are learning to FOIL now.
Directrix (directrix):
No.
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OpenStudy (anonymous):
5a³
Directrix (directrix):
5 a^2 means 5 times a times a. Then, multiply that by a.
So, what is 5 times a times a times a?
OpenStudy (anonymous):
not 5a³?
Directrix (directrix):
5 times a times a times a = 5a³. (F)
O is for the outer terms. The outer terms are on the outside.
What does 5A^2 times 3 =
OpenStudy (anonymous):
15a²
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Directrix (directrix):
15a² (O)
I is for inner.
The inner terms are (-6) and (a). What is the product of (-6) and (a) ?
OpenStudy (anonymous):
-6a?
Directrix (directrix):
-6a (I)
L is for last. What is the product of (-6) and (3) ?
Directrix (directrix):
@JaneDoe100
OpenStudy (anonymous):
-12
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OpenStudy (anonymous):
i think i get what i was doing wrong now thanks!!!
Directrix (directrix):
-18 for L (-6)*(3) = -18
Directrix (directrix):
F) 5a^3
O) 15a^2
I) -6a
L) -18
OpenStudy (anonymous):
so its (5a²-6)(a+3) because that factored out to the right problem
Directrix (directrix):
(5a²-6)(a+3) = 5a^3 + 15a^2 -6a -18 = 5a^3 + 15a^2 - 6a - 18.
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Directrix (directrix):
Yes.
OpenStudy (anonymous):
thanks