(5y-1)(7+y)=0

Solution for (5y-1)(7+y)=0 equation:

(5y-1)(7+y)=0

We add all the numbers together, and all the variables

(5y-1)(y+7)=0

We multiply parentheses ..

(+5y^2+35y-1y-7)=0

We get rid of parentheses

5y^2+35y-1y-7=0

We add all the numbers together, and all the variables

5y^2+34y-7=0

a = 5; b = 34; c = -7;
Δ = b2-4ac
Δ = 342-4·5·(-7)
Δ = 1296
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1296}=36$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(34)-36}{2*5}=\frac{-70}{10}
=-7
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(34)+36}{2*5}=\frac{2}{10}
=1/5
$