Y=x2+400x

Solution for Y=x2+400x equation:

=Y2+400Y

We move all terms to the left:

-(Y2+400Y)=0

We add all the numbers together, and all the variables

-(+Y^2+400Y)=0

We get rid of parentheses

-Y^2-400Y=0

We add all the numbers together, and all the variables

-1Y^2-400Y=0

a = -1; b = -400; c = 0;
Δ = b2-4ac
Δ = -4002-4·(-1)·0
Δ = 160000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{160000}=400$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-400)-400}{2*-1}=\frac{0}{-2}
=0
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-400)+400}{2*-1}=\frac{800}{-2}
=-400
$