2(x+4)(2x+5)=0

Solution for 2(x+4)(2x+5)=0 equation:

2(x+4)(2x+5)=0

We multiply parentheses ..

2(+2x^2+5x+8x+20)=0

We multiply parentheses

4x^2+10x+16x+40=0

We add all the numbers together, and all the variables

4x^2+26x+40=0

a = 4; b = 26; c = +40;
Δ = b2-4ac
Δ = 262-4·4·40
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(26)-6}{2*4}=\frac{-32}{8}
=-4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(26)+6}{2*4}=\frac{-20}{8}
=-2+1/2
$