10=5(y+6)7y

Solution for 10=5(y+6)7y equation:

10=5(y+6)7y

We move all terms to the left:

10-(5(y+6)7y)=0


We calculate terms in parentheses: -(5(y+6)7y), so:

5(y+6)7y

We multiply parentheses

35y^2+210y

Back to the equation:

-(35y^2+210y)


We get rid of parentheses

-35y^2-210y+10=0

a = -35; b = -210; c = +10;
Δ = b2-4ac
Δ = -2102-4·(-35)·10
Δ = 45500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{45500}=\sqrt{100*455}=\sqrt{100}*\sqrt{455}=10\sqrt{455}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-210)-10\sqrt{455}}{2*-35}=\frac{210-10\sqrt{455}}{-70}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-210)+10\sqrt{455}}{2*-35}=\frac{210+10\sqrt{455}}{-70}
$