-y^2+6y=-1

Solution for -y^2+6y=-1 equation:

-y^2+6y=-1

We move all terms to the left:

-y^2+6y-(-1)=0

We add all the numbers together, and all the variables

-1y^2+6y+1=0

a = -1; b = 6; c = +1;
Δ = b2-4ac
Δ = 62-4·(-1)·1
Δ = 40
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{40}=\sqrt{4*10}=\sqrt{4}*\sqrt{10}=2\sqrt{10}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-2\sqrt{10}}{2*-1}=\frac{-6-2\sqrt{10}}{-2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+2\sqrt{10}}{2*-1}=\frac{-6+2\sqrt{10}}{-2}
$