G(3)=x2-5+7

Solution for G(3)=x2-5+7 equation:

(3)=G2-5+7

We move all terms to the left:

(3)-(G2-5+7)=0

We add all the numbers together, and all the variables

-(+G^2-5+7)+3=0

We get rid of parentheses

-G^2+5-7+3=0

We add all the numbers together, and all the variables

-1G^2+1=0

a = -1; b = 0; c = +1;
Δ = b2-4ac
Δ = 02-4·(-1)·1
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$G_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$G_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$G_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2}{2*-1}=\frac{-2}{-2}
=1
$
$G_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2}{2*-1}=\frac{2}{-2}
=-1
$