A-1.5a(a+8)=10

Solution for A-1.5a(a+8)=10 equation:

-1.5A(A+8)=10

We move all terms to the left:

-1.5A(A+8)-(10)=0

We multiply parentheses

-A^2-8A-10=0

We add all the numbers together, and all the variables

-1A^2-8A-10=0

a = -1; b = -8; c = -10;
Δ = b2-4ac
Δ = -82-4·(-1)·(-10)
Δ = 24
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{24}=\sqrt{4*6}=\sqrt{4}*\sqrt{6}=2\sqrt{6}$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-2\sqrt{6}}{2*-1}=\frac{8-2\sqrt{6}}{-2}
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+2\sqrt{6}}{2*-1}=\frac{8+2\sqrt{6}}{-2}
$