(5-b)(12+5b)=0

Solution for (5-b)(12+5b)=0 equation:

(5-b)(12+5b)=0

We add all the numbers together, and all the variables

(-1b+5)(5b+12)=0

We multiply parentheses ..

(-5b^2-12b+25b+60)=0

We get rid of parentheses

-5b^2-12b+25b+60=0

We add all the numbers together, and all the variables

-5b^2+13b+60=0

a = -5; b = 13; c = +60;
Δ = b2-4ac
Δ = 132-4·(-5)·60
Δ = 1369
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1369}=37$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-37}{2*-5}=\frac{-50}{-10}
=+5
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+37}{2*-5}=\frac{24}{-10}
=-2+2/5
$