7x(13x-5)=56

Solution for 7x(13x-5)=56 equation:

7x(13x-5)=56

We move all terms to the left:

7x(13x-5)-(56)=0

We multiply parentheses

91x^2-35x-56=0

a = 91; b = -35; c = -56;
Δ = b2-4ac
Δ = -352-4·91·(-56)
Δ = 21609
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{21609}=147$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-35)-147}{2*91}=\frac{-112}{182}
=-8/13
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-35)+147}{2*91}=\frac{182}{182}
=1
$