(8x-9)(5x+7)=0

Solution for (8x-9)(5x+7)=0 equation:

(8x-9)(5x+7)=0

We multiply parentheses ..

(+40x^2+56x-45x-63)=0

We get rid of parentheses

40x^2+56x-45x-63=0

We add all the numbers together, and all the variables

40x^2+11x-63=0

a = 40; b = 11; c = -63;
Δ = b2-4ac
Δ = 112-4·40·(-63)
Δ = 10201
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{10201}=101$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(11)-101}{2*40}=\frac{-112}{80}
=-1+2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(11)+101}{2*40}=\frac{90}{80}
=1+1/8
$