x=4x2-15x

Solution for x=4x2-15x equation:

x=4x^2-15x

We move all terms to the left:

x-(4x^2-15x)=0

We get rid of parentheses

-4x^2+x+15x=0

We add all the numbers together, and all the variables

-4x^2+16x=0

a = -4; b = 16; c = 0;
Δ = b2-4ac
Δ = 162-4·(-4)·0
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-16}{2*-4}=\frac{-32}{-8}
=+4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+16}{2*-4}=\frac{0}{-8}
=0
$