A=16s^2+25s

Solution for A=16s^2+25s equation:

=16A^2+25A

We move all terms to the left:

-(16A^2+25A)=0

We get rid of parentheses

-16A^2-25A=0

a = -16; b = -25; c = 0;
Δ = b2-4ac
Δ = -252-4·(-16)·0
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-25}{2*-16}=\frac{0}{-32}
=0
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+25}{2*-16}=\frac{50}{-32}
=-1+9/16
$