Y=x^2-16x+15

Solution for Y=x^2-16x+15 equation:

=Y^2-16Y+15

We move all terms to the left:

-(Y^2-16Y+15)=0

We get rid of parentheses

-Y^2+16Y-15=0

We add all the numbers together, and all the variables

-1Y^2+16Y-15=0

a = -1; b = 16; c = -15;
Δ = b2-4ac
Δ = 162-4·(-1)·(-15)
Δ = 196
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{196}=14$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-14}{2*-1}=\frac{-30}{-2}
=+15
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+14}{2*-1}=\frac{-2}{-2}
=1
$