(8x+7)(x+6)=0

Solution for (8x+7)(x+6)=0 equation:

(8x+7)(x+6)=0

We multiply parentheses ..

(+8x^2+48x+7x+42)=0

We get rid of parentheses

8x^2+48x+7x+42=0

We add all the numbers together, and all the variables

8x^2+55x+42=0

a = 8; b = 55; c = +42;
Δ = b2-4ac
Δ = 552-4·8·42
Δ = 1681
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1681}=41$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(55)-41}{2*8}=\frac{-96}{16}
=-6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(55)+41}{2*8}=\frac{-14}{16}
=-7/8
$