(2a+8)(a+1)=0

Solution for (2a+8)(a+1)=0 equation:

(2a+8)(a+1)=0

We multiply parentheses ..

(+2a^2+2a+8a+8)=0

We get rid of parentheses

2a^2+2a+8a+8=0

We add all the numbers together, and all the variables

2a^2+10a+8=0

a = 2; b = 10; c = +8;
Δ = b2-4ac
Δ = 102-4·2·8
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-6}{2*2}=\frac{-16}{4}
=-4
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+6}{2*2}=\frac{-4}{4}
=-1
$