(8a)(5a-2)=180

Solution for (8a)(5a-2)=180 equation:

(8a)(5a-2)=180

We move all terms to the left:

(8a)(5a-2)-(180)=0

We multiply parentheses

40a^2-16a-180=0

a = 40; b = -16; c = -180;
Δ = b2-4ac
Δ = -162-4·40·(-180)
Δ = 29056
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:

$\sqrt{\Delta}=\sqrt{29056}=\sqrt{64*454}=\sqrt{64}*\sqrt{454}=8\sqrt{454}$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-8\sqrt{454}}{2*40}=\frac{16-8\sqrt{454}}{80}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+8\sqrt{454}}{2*40}=\frac{16+8\sqrt{454}}{80}
$