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Mathematics 14 Online
OpenStudy (anonymous):

solve 2x^2+x=15

OpenStudy (anonymous):

x=5/2 or x=-3

OpenStudy (anonymous):

how did you get that?

OpenStudy (jhannybean):

\[2x^2+x=15\]Move the 15 over by subtracting -15 from both sides. \[2x^2+x-15=0\]Now factor this. I use the BUM method (don't ask me why it's called that).\[x^2 +x -30=0\]\[(x+6)(x-5)=0\]\[\left(x+\frac{6}{2}\right)\left(x-\frac{5}{2}\right)=0\]\[(x+3)(2x-5)=0\]

OpenStudy (jhannybean):

Solving for your factors, \[x+3=0 \implies x=-3\]\[2x-5=0 \implies x = \frac{5}{2} \]

OpenStudy (anonymous):

Yeah that makes a lot more sense, thanks :)

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