315=(2x-9)(x)

Solution for 315=(2x-9)(x) equation:

315=(2x-9)(x)

We move all terms to the left:

315-((2x-9)(x))=0


We calculate terms in parentheses: -((2x-9)x), so:

(2x-9)x

We multiply parentheses

2x^2-9x

Back to the equation:

-(2x^2-9x)


We get rid of parentheses

-2x^2+9x+315=0

a = -2; b = 9; c = +315;
Δ = b2-4ac
Δ = 92-4·(-2)·315
Δ = 2601
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2601}=51$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-51}{2*-2}=\frac{-60}{-4}
=+15
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+51}{2*-2}=\frac{42}{-4}
=-10+1/2
$