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Mathematics 17 Online
OpenStudy (anonymous):

3x^3+19x^2-72x=0

Parth (parthkohli):

Divide both sides by \(x\).\[3x^2 + 19x - 72 = 0 \]Now, solve this quadratic equation.

OpenStudy (anonymous):

ok

OpenStudy (anonymous):

Hint: x+9 is a factor of the quadratic.

OpenStudy (anonymous):

is the other (3x-8)

OpenStudy (anonymous):

Yes.

OpenStudy (anonymous):

ok but when i add -8+9 it does not equal 19

OpenStudy (anonymous):

why is that?

OpenStudy (anonymous):

\[(x+9) (3 x-8)=3x^2+27x-8x-72=3 x^2+19 x-72 \]

OpenStudy (anonymous):

ok...so then how would i get the 3x^3 and 19x^2 back??

OpenStudy (anonymous):

\[x*\left(3 x^2+19 x-72\right)=3 x^3+19 x^2-72 x \]

OpenStudy (anonymous):

ok thanks!!

OpenStudy (anonymous):

You're welcome.

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