(8x+7)(9x+6)=0

Solution for (8x+7)(9x+6)=0 equation:

(8x+7)(9x+6)=0

We multiply parentheses ..

(+72x^2+48x+63x+42)=0

We get rid of parentheses

72x^2+48x+63x+42=0

We add all the numbers together, and all the variables

72x^2+111x+42=0

a = 72; b = 111; c = +42;
Δ = b2-4ac
Δ = 1112-4·72·42
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(111)-15}{2*72}=\frac{-126}{144}
=-7/8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(111)+15}{2*72}=\frac{-96}{144}
=-2/3
$