x^2+9=4x+57

Solution for x^2+9=4x+57 equation:

x^2+9=4x+57

We move all terms to the left:

x^2+9-(4x+57)=0

We get rid of parentheses

x^2-4x-57+9=0

We add all the numbers together, and all the variables

x^2-4x-48=0

a = 1; b = -4; c = -48;
Δ = b2-4ac
Δ = -42-4·1·(-48)
Δ = 208
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{208}=\sqrt{16*13}=\sqrt{16}*\sqrt{13}=4\sqrt{13}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-4\sqrt{13}}{2*1}=\frac{4-4\sqrt{13}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+4\sqrt{13}}{2*1}=\frac{4+4\sqrt{13}}{2}
$