625=16x^2+64x+64+x^2+6x+9

Solution for 625=16x^2+64x+64+x^2+6x+9 equation:

625=16x^2+64x+64+x^2+6x+9

We move all terms to the left:

625-(16x^2+64x+64+x^2+6x+9)=0

We get rid of parentheses

-16x^2-x^2-64x-6x-64-9+625=0

We add all the numbers together, and all the variables

-17x^2-70x+552=0

a = -17; b = -70; c = +552;
Δ = b2-4ac
Δ = -702-4·(-17)·552
Δ = 42436
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{42436}=206$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-70)-206}{2*-17}=\frac{-136}{-34}
=+4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-70)+206}{2*-17}=\frac{276}{-34}
=-8+2/17
$