X2=-x+1

Solution for X2=-x+1 equation:

X2=-X+1

We move all terms to the left:

X2-(-X+1)=0

We add all the numbers together, and all the variables

X2-(-1X+1)=0

We add all the numbers together, and all the variables

X^2-(-1X+1)=0

We get rid of parentheses

X^2+1X-1=0

We add all the numbers together, and all the variables

X^2+X-1=0

a = 1; b = 1; c = -1;
Δ = b2-4ac
Δ = 12-4·1·(-1)
Δ = 5
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-\sqrt{5}}{2*1}=\frac{-1-\sqrt{5}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{5}}{2*1}=\frac{-1+\sqrt{5}}{2}
$