(8x+5)(x+5)=0

Solution for (8x+5)(x+5)=0 equation:

(8x+5)(x+5)=0

We multiply parentheses ..

(+8x^2+40x+5x+25)=0

We get rid of parentheses

8x^2+40x+5x+25=0

We add all the numbers together, and all the variables

8x^2+45x+25=0

a = 8; b = 45; c = +25;
Δ = b2-4ac
Δ = 452-4·8·25
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(45)-35}{2*8}=\frac{-80}{16}
=-5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(45)+35}{2*8}=\frac{-10}{16}
=-5/8
$