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How do you factor when "a" is greater than 1? Pls show work

Pls show work so I can understand

4 x^2 - 7x - 15

User Sycx
by
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1 Answer

7 votes
for
ax^2+bx+c
if a≠1 then
first seee if you can undsitribute a
ifyou can't
use the ac method

multiply a and c
find 2 numbers that add to b and multiply to get ac
split b into that
group
undistribute
undistribute


so


4x^2-7x-15
ac=4*-15=-60
what 2 numbers multiply to get -60 and add to get -7?
5 and -12
split b up into -12 and 5

4x^2-12x+5x-15
group

(4x^2-12x)+(5x-15)
undistribute

4x(x-3)+5(x-3)
undistribute

(4x+5)(x-3)
User Saddy
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8.1k points

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