(5+y)(5y+9)=0

Solution for (5+y)(5y+9)=0 equation:

(5+y)(5y+9)=0

We add all the numbers together, and all the variables

(y+5)(5y+9)=0

We multiply parentheses ..

(+5y^2+9y+25y+45)=0

We get rid of parentheses

5y^2+9y+25y+45=0

We add all the numbers together, and all the variables

5y^2+34y+45=0

a = 5; b = 34; c = +45;
Δ = b2-4ac
Δ = 342-4·5·45
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(34)-16}{2*5}=\frac{-50}{10}
=-5
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(34)+16}{2*5}=\frac{-18}{10}
=-1+4/5
$