38.7=4x^2-36x

Solution for 38.7=4x^2-36x equation:

38.7=4x^2-36x

We move all terms to the left:

38.7-(4x^2-36x)=0

We get rid of parentheses

-4x^2+36x+38.7=0

a = -4; b = 36; c = +38.7;
Δ = b2-4ac
Δ = 362-4·(-4)·38.7
Δ = 1915.2
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{-(36)-\sqrt{1915.2}}{2*-4}=\frac{-36-\sqrt{1915.2}}{-8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(36)+\sqrt{1915.2}}{2*-4}=\frac{-36+\sqrt{1915.2}}{-8}
$