Y=3x^2-20,x=5

Solution for Y=3x^2-20,x=5 equation:

=3Y^2-20.Y=5

We move all terms to the left:

-(3Y^2-20.Y)=0

We get rid of parentheses

-3Y^2+20.Y=0

a = -3; b = 20.; c = 0;
Δ = b2-4ac
Δ = 20.2-4·(-3)·0
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20.)-20}{2*-3}=\frac{-40}{-6}
=6+2/3
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20.)+20}{2*-3}=\frac{0}{-6}
=0
$