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

Solution for (6+y)(5y-7)=0 equation:

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

We add all the numbers together, and all the variables

(y+6)(5y-7)=0

We multiply parentheses ..

(+5y^2-7y+30y-42)=0

We get rid of parentheses

5y^2-7y+30y-42=0

We add all the numbers together, and all the variables

5y^2+23y-42=0

a = 5; b = 23; c = -42;
Δ = b2-4ac
Δ = 232-4·5·(-42)
Δ = 1369
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1369}=37$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(23)-37}{2*5}=\frac{-60}{10}
=-6
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(23)+37}{2*5}=\frac{14}{10}
=1+2/5
$