Y=5x2-30x-25

Solution for Y=5x2-30x-25 equation:

=5Y^2-30Y-25

We move all terms to the left:

-(5Y^2-30Y-25)=0

We get rid of parentheses

-5Y^2+30Y+25=0

a = -5; b = 30; c = +25;
Δ = b2-4ac
Δ = 302-4·(-5)·25
Δ = 1400
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:

$\sqrt{\Delta}=\sqrt{1400}=\sqrt{100*14}=\sqrt{100}*\sqrt{14}=10\sqrt{14}$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-10\sqrt{14}}{2*-5}=\frac{-30-10\sqrt{14}}{-10}
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+10\sqrt{14}}{2*-5}=\frac{-30+10\sqrt{14}}{-10}
$