6-3y(y+2)+4y=5

Solution for 6-3y(y+2)+4y=5 equation:

6-3y(y+2)+4y=5

We move all terms to the left:

6-3y(y+2)+4y-(5)=0

We add all the numbers together, and all the variables

4y-3y(y+2)+1=0

We multiply parentheses

-3y^2+4y-6y+1=0

We add all the numbers together, and all the variables

-3y^2-2y+1=0

a = -3; b = -2; c = +1;
Δ = b2-4ac
Δ = -22-4·(-3)·1
Δ = 16
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16}=4$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-4}{2*-3}=\frac{-2}{-6}
=1/3
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+4}{2*-3}=\frac{6}{-6}
=-1
$