A=(5x-6)(4x-3)

Solution for A=(5x-6)(4x-3) equation:

=(5A-6)(4A-3)

We move all terms to the left:

-((5A-6)(4A-3))=0

We multiply parentheses ..

-((+20A^2-15A-24A+18))=0


We calculate terms in parentheses: -((+20A^2-15A-24A+18)), so:

(+20A^2-15A-24A+18)

We get rid of parentheses

20A^2-15A-24A+18

We add all the numbers together, and all the variables

20A^2-39A+18

Back to the equation:

-(20A^2-39A+18)


We get rid of parentheses

-20A^2+39A-18=0

a = -20; b = 39; c = -18;
Δ = b2-4ac
Δ = 392-4·(-20)·(-18)
Δ = 81
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{81}=9$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(39)-9}{2*-20}=\frac{-48}{-40}
=1+1/5
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(39)+9}{2*-20}=\frac{-30}{-40}
=3/4
$