0=18y-y2-77

Solution for 0=18y-y2-77 equation:

0=18y-y2-77

We move all terms to the left:

0-(18y-y2-77)=0

We add all the numbers together, and all the variables

-(+18y-1y^2-77)+0=0

We add all the numbers together, and all the variables

-(+18y-1y^2-77)=0

We get rid of parentheses

1y^2-18y+77=0

We add all the numbers together, and all the variables

y^2-18y+77=0

a = 1; b = -18; c = +77;
Δ = b2-4ac
Δ = -182-4·1·77
Δ = 16
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16}=4$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-4}{2*1}=\frac{14}{2}
=7
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+4}{2*1}=\frac{22}{2}
=11
$