(50-2a)(3a+21)=0

Solution for (50-2a)(3a+21)=0 equation:

(50-2a)(3a+21)=0

We add all the numbers together, and all the variables

(-2a+50)(3a+21)=0

We multiply parentheses ..

(-6a^2-42a+150a+1050)=0

We get rid of parentheses

-6a^2-42a+150a+1050=0

We add all the numbers together, and all the variables

-6a^2+108a+1050=0

a = -6; b = 108; c = +1050;
Δ = b2-4ac
Δ = 1082-4·(-6)·1050
Δ = 36864
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36864}=192$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(108)-192}{2*-6}=\frac{-300}{-12}
=+25
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(108)+192}{2*-6}=\frac{84}{-12}
=-7
$