8x(9x+7)=0

Solution for 8x(9x+7)=0 equation:

8x(9x+7)=0

We multiply parentheses

72x^2+56x=0

a = 72; b = 56; c = 0;
Δ = b2-4ac
Δ = 562-4·72·0
Δ = 3136
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3136}=56$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(56)-56}{2*72}=\frac{-112}{144}
=-7/9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(56)+56}{2*72}=\frac{0}{144}
=0
$