(4+y)(4y+9)=0

Solution for (4+y)(4y+9)=0 equation:

(4+y)(4y+9)=0

We add all the numbers together, and all the variables

(y+4)(4y+9)=0

We multiply parentheses ..

(+4y^2+9y+16y+36)=0

We get rid of parentheses

4y^2+9y+16y+36=0

We add all the numbers together, and all the variables

4y^2+25y+36=0

a = 4; b = 25; c = +36;
Δ = b2-4ac
Δ = 252-4·4·36
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{-(25)-7}{2*4}=\frac{-32}{8}
=-4
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+7}{2*4}=\frac{-18}{8}
=-2+1/4
$