x(5x-2)=115

Solution for x(5x-2)=115 equation:

x(5x-2)=115

We move all terms to the left:

x(5x-2)-(115)=0

We multiply parentheses

5x^2-2x-115=0

a = 5; b = -2; c = -115;
Δ = b2-4ac
Δ = -22-4·5·(-115)
Δ = 2304
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2304}=48$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-48}{2*5}=\frac{-46}{10}
=-4+3/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+48}{2*5}=\frac{50}{10}
=5
$