7z^2-2=0

Solution for 7z^2-2=0 equation:

7z^2-2=0

a = 7; b = 0; c = -2;
Δ = b2-4ac
Δ = 02-4·7·(-2)
Δ = 56
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{56}=\sqrt{4*14}=\sqrt{4}*\sqrt{14}=2\sqrt{14}$
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{14}}{2*7}=\frac{0-2\sqrt{14}}{14}
=-\frac{2\sqrt{14}}{14}
=-\frac{\sqrt{14}}{7}
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{14}}{2*7}=\frac{0+2\sqrt{14}}{14}
=\frac{2\sqrt{14}}{14}
=\frac{\sqrt{14}}{7}
$