-5(y-1)(-y-2)=0

Solution for -5(y-1)(-y-2)=0 equation:

-5(y-1)(-y-2)=0

We add all the numbers together, and all the variables

-5(y-1)(-1y-2)=0

We multiply parentheses ..

-5(-1y^2-2y+y+2)=0

We multiply parentheses

5y^2+10y-5y-10=0

We add all the numbers together, and all the variables

5y^2+5y-10=0

a = 5; b = 5; c = -10;
Δ = b2-4ac
Δ = 52-4·5·(-10)
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-15}{2*5}=\frac{-20}{10}
=-2
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+15}{2*5}=\frac{10}{10}
=1
$