(3-5x)(2x+10)=0

Solution for (3-5x)(2x+10)=0 equation:

(3-5x)(2x+10)=0

We add all the numbers together, and all the variables

(-5x+3)(2x+10)=0

We multiply parentheses ..

(-10x^2-50x+6x+30)=0

We get rid of parentheses

-10x^2-50x+6x+30=0

We add all the numbers together, and all the variables

-10x^2-44x+30=0

a = -10; b = -44; c = +30;
Δ = b2-4ac
Δ = -442-4·(-10)·30
Δ = 3136
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3136}=56$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-44)-56}{2*-10}=\frac{-12}{-20}
=3/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-44)+56}{2*-10}=\frac{100}{-20}
=-5
$