(x+5)(10+4x)=0

Solution for (x+5)(10+4x)=0 equation:

(x+5)(10+4x)=0

We add all the numbers together, and all the variables

(x+5)(4x+10)=0

We multiply parentheses ..

(+4x^2+10x+20x+50)=0

We get rid of parentheses

4x^2+10x+20x+50=0

We add all the numbers together, and all the variables

4x^2+30x+50=0

a = 4; b = 30; c = +50;
Δ = b2-4ac
Δ = 302-4·4·50
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-10}{2*4}=\frac{-40}{8}
=-5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+10}{2*4}=\frac{-20}{8}
=-2+1/2
$