x^2-0.36x=4

Solution for x^2-0.36x=4 equation:

x^2-0.36x=4

We move all terms to the left:

x^2-0.36x-(4)=0

a = 1; b = -0.36; c = -4;
Δ = b2-4ac
Δ = -0.362-4·1·(-4)
Δ = 16.1296
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{-(-0.36)-\sqrt{16.1296}}{2*1}=\frac{0.36-\sqrt{16.1296}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.36)+\sqrt{16.1296}}{2*1}=\frac{0.36+\sqrt{16.1296}}{2}
$