-2(a-8)7a=36

Solution for -2(a-8)7a=36 equation:

-2(a-8)7a=36

We move all terms to the left:

-2(a-8)7a-(36)=0

We multiply parentheses

-14a^2+112a-36=0

a = -14; b = 112; c = -36;
Δ = b2-4ac
Δ = 1122-4·(-14)·(-36)
Δ = 10528
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{10528}=\sqrt{16*658}=\sqrt{16}*\sqrt{658}=4\sqrt{658}$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(112)-4\sqrt{658}}{2*-14}=\frac{-112-4\sqrt{658}}{-28}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(112)+4\sqrt{658}}{2*-14}=\frac{-112+4\sqrt{658}}{-28}
$