A=8x^2+22x+15

Solution for A=8x^2+22x+15 equation:

=8A^2+22A+15

We move all terms to the left:

-(8A^2+22A+15)=0

We get rid of parentheses

-8A^2-22A-15=0

a = -8; b = -22; c = -15;
Δ = b2-4ac
Δ = -222-4·(-8)·(-15)
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-22)-2}{2*-8}=\frac{20}{-16}
=-1+1/4
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-22)+2}{2*-8}=\frac{24}{-16}
=-1+1/2
$