Question

How do you solve `6-2x^2=9x+15` using the quadratic formula?

Answer 1

`x = -3`

`x = -3/2`

Explanation:

Get all the terms on the left side and rearrange:

`-2x^2 - 9x -9 = 0`

Apply the quadratic formula knowing `a=-2, b=-9, c=-9`:

`x_(1,2) = (-(-9) +- sqrt( (-9)^2 - 4 * (-2) * (-9)))/(2 * (-2))`

`x_(1,2) = (9 +- sqrt(81 - 72))/-4 = (9+-3)/-4 => {(x_1 = 12/-4 = -3), (x_2 = 6/-4 = -3/2) :}`