-5y(2y=30)+5=40

Solution for -5y(2y=30)+5=40 equation:

-5y(2y=30)+5=40

We move all terms to the left:

-5y(2y-(30)+5)=0

We add all the numbers together, and all the variables

-5y(2y-25)=0

We multiply parentheses

-10y^2+125y=0

a = -10; b = 125; c = 0;
Δ = b2-4ac
Δ = 1252-4·(-10)·0
Δ = 15625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{15625}=125$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(125)-125}{2*-10}=\frac{-250}{-20}
=12+1/2
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(125)+125}{2*-10}=\frac{0}{-20}
=0
$