5x^2+4x=220

Solution for 5x^2+4x=220 equation:

5x^2+4x=220

We move all terms to the left:

5x^2+4x-(220)=0

a = 5; b = 4; c = -220;
Δ = b2-4ac
Δ = 42-4·5·(-220)
Δ = 4416
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{4416}=\sqrt{64*69}=\sqrt{64}*\sqrt{69}=8\sqrt{69}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-8\sqrt{69}}{2*5}=\frac{-4-8\sqrt{69}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+8\sqrt{69}}{2*5}=\frac{-4+8\sqrt{69}}{10}
$