-5r(1-5r)+5(-8r-2)=-4r-8r

Solution for -5r(1-5r)+5(-8r-2)=-4r-8r equation:

-5r(1-5r)+5(-8r-2)=-4r-8r

We move all terms to the left:

-5r(1-5r)+5(-8r-2)-(-4r-8r)=0

We add all the numbers together, and all the variables

-5r(-5r+1)+5(-8r-2)-(-12r)=0

We multiply parentheses

25r^2-5r-40r-(-12r)-10=0

We get rid of parentheses

25r^2-5r-40r+12r-10=0

We add all the numbers together, and all the variables

25r^2-33r-10=0

a = 25; b = -33; c = -10;
Δ = b2-4ac
Δ = -332-4·25·(-10)
Δ = 2089
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-33)-\sqrt{2089}}{2*25}=\frac{33-\sqrt{2089}}{50}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-33)+\sqrt{2089}}{2*25}=\frac{33+\sqrt{2089}}{50}
$