70x^2-40=0

Solution for 70x^2-40=0 equation:

70x^2-40=0

a = 70; b = 0; c = -40;
Δ = b2-4ac
Δ = 02-4·70·(-40)
Δ = 11200
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{11200}=\sqrt{1600*7}=\sqrt{1600}*\sqrt{7}=40\sqrt{7}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-40\sqrt{7}}{2*70}=\frac{0-40\sqrt{7}}{140}
=-\frac{40\sqrt{7}}{140}
=-\frac{2\sqrt{7}}{7}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+40\sqrt{7}}{2*70}=\frac{0+40\sqrt{7}}{140}
=\frac{40\sqrt{7}}{140}
=\frac{2\sqrt{7}}{7}
$