0=y(y-7)

Solution for 0=y(y-7) equation:

0=y(y-7)

We move all terms to the left:

0-(y(y-7))=0

We add all the numbers together, and all the variables

-(y(y-7))=0


We calculate terms in parentheses: -(y(y-7)), so:

y(y-7)

We multiply parentheses

y^2-7y

Back to the equation:

-(y^2-7y)


We get rid of parentheses

-y^2+7y=0

We add all the numbers together, and all the variables

-1y^2+7y=0

a = -1; b = 7; c = 0;
Δ = b2-4ac
Δ = 72-4·(-1)·0
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-7}{2*-1}=\frac{-14}{-2}
=+7
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+7}{2*-1}=\frac{0}{-2}
=0
$