(5y+2)(4y)=220

Solution for (5y+2)(4y)=220 equation:

(5y+2)(4y)=220

We move all terms to the left:

(5y+2)(4y)-(220)=0

We multiply parentheses

20y^2+8y-220=0

a = 20; b = 8; c = -220;
Δ = b2-4ac
Δ = 82-4·20·(-220)
Δ = 17664
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{17664}=\sqrt{256*69}=\sqrt{256}*\sqrt{69}=16\sqrt{69}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-16\sqrt{69}}{2*20}=\frac{-8-16\sqrt{69}}{40}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+16\sqrt{69}}{2*20}=\frac{-8+16\sqrt{69}}{40}
$