360=x(4x+5)

Solution for 360=x(4x+5) equation:

360=x(4x+5)

We move all terms to the left:

360-(x(4x+5))=0


We calculate terms in parentheses: -(x(4x+5)), so:

x(4x+5)

We multiply parentheses

4x^2+5x

Back to the equation:

-(4x^2+5x)


We get rid of parentheses

-4x^2-5x+360=0

a = -4; b = -5; c = +360;
Δ = b2-4ac
Δ = -52-4·(-4)·360
Δ = 5785
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-\sqrt{5785}}{2*-4}=\frac{5-\sqrt{5785}}{-8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+\sqrt{5785}}{2*-4}=\frac{5+\sqrt{5785}}{-8}
$