I am confused about solving A=4P(1+x)^2
solve for X in terms of A and P

A=4P(1+x)^{2}

Divide by 4P:

\frac{A}{4P}=(1+x)^{2}

Square root both sides:

\pm\sqrt{\frac{A}{4P}}=1+x

x=\pm\sqrt{\frac{A}{4P}}-1

There. See how that was done? To get rid of the square, just take the square root of both sides. If it were a cube, then take the cube root of both sides, and so on.