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 Question from Ashley, a student: I have to solve using the quadratic formula. And my answer should be in simplest exact form. And I can't approximate. I really need help to prepare for a test .... x(x-3) = 5 (x+4)

Hi Ashley,

To use the quadratic formula you need the the quadratic equation in the form $a x^2 + b x + c = 0.$ To obtain this from your equation first expand both sides to get

$x(x-3) = 5 (x+4) = x^2 - 3x = 5x + 20$

and then subtract $5x + 20$ from both sides and simplify. Now you should be able to use the quadratic formula.

Penny

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