(16-2y)y=28

Solution for (16-2y)y=28 equation:

(16-2y)y=28

We move all terms to the left:

(16-2y)y-(28)=0

We add all the numbers together, and all the variables

(-2y+16)y-28=0

We multiply parentheses

-2y^2+16y-28=0

a = -2; b = 16; c = -28;
Δ = b2-4ac
Δ = 162-4·(-2)·(-28)
Δ = 32
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:

$\sqrt{\Delta}=\sqrt{32}=\sqrt{16*2}=\sqrt{16}*\sqrt{2}=4\sqrt{2}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-4\sqrt{2}}{2*-2}=\frac{-16-4\sqrt{2}}{-4}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+4\sqrt{2}}{2*-2}=\frac{-16+4\sqrt{2}}{-4}
$