A=(3x+8)(2x-8)

Solution for A=(3x+8)(2x-8) equation:

=(3A+8)(2A-8)

We move all terms to the left:

-((3A+8)(2A-8))=0

We multiply parentheses ..

-((+6A^2-24A+16A-64))=0


We calculate terms in parentheses: -((+6A^2-24A+16A-64)), so:

(+6A^2-24A+16A-64)

We get rid of parentheses

6A^2-24A+16A-64

We add all the numbers together, and all the variables

6A^2-8A-64

Back to the equation:

-(6A^2-8A-64)


We get rid of parentheses

-6A^2+8A+64=0

a = -6; b = 8; c = +64;
Δ = b2-4ac
Δ = 82-4·(-6)·64
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-40}{2*-6}=\frac{-48}{-12}
=+4
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+40}{2*-6}=\frac{32}{-12}
=-2+2/3
$