(X+6)(5-2x)=0

Solution for (X+6)(5-2x)=0 equation:

(X+6)(5-2X)=0

We add all the numbers together, and all the variables

(X+6)(-2X+5)=0

We multiply parentheses ..

(-2X^2+5X-12X+30)=0

We get rid of parentheses

-2X^2+5X-12X+30=0

We add all the numbers together, and all the variables

-2X^2-7X+30=0

a = -2; b = -7; c = +30;
Δ = b2-4ac
Δ = -72-4·(-2)·30
Δ = 289
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{289}=17$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-17}{2*-2}=\frac{-10}{-4}
=2+1/2
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+17}{2*-2}=\frac{24}{-4}
=-6
$