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

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

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

We add all the numbers together, and all the variables

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

We multiply parentheses ..

(-63x^2+72x+49x-56)=0

We get rid of parentheses

-63x^2+72x+49x-56=0

We add all the numbers together, and all the variables

-63x^2+121x-56=0

a = -63; b = 121; c = -56;
Δ = b2-4ac
Δ = 1212-4·(-63)·(-56)
Δ = 529
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{529}=23$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(121)-23}{2*-63}=\frac{-144}{-126}
=1+1/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(121)+23}{2*-63}=\frac{-98}{-126}
=7/9
$