y(y+4)=-3.75

Solution for y(y+4)=-3.75 equation:

y(y+4)=-3.75

We move all terms to the left:

y(y+4)-(-3.75)=0

We add all the numbers together, and all the variables

y(y+4)+3.75=0

We multiply parentheses

y^2+4y+3.75=0

a = 1; b = 4; c = +3.75;
Δ = b2-4ac
Δ = 42-4·1·3.75
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-1}{2*1}=\frac{-5}{2}
=-2+1/2
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+1}{2*1}=\frac{-3}{2}
=-1+1/2
$