x*x*7=30

Solution for x*x*7=30 equation:

x*x*7=30

We move all terms to the left:

x*x*7-(30)=0

Wy multiply elements

7x^2*7-30=0

Wy multiply elements

49x^2-30=0

a = 49; b = 0; c = -30;
Δ = b2-4ac
Δ = 02-4·49·(-30)
Δ = 5880
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:

$\sqrt{\Delta}=\sqrt{5880}=\sqrt{196*30}=\sqrt{196}*\sqrt{30}=14\sqrt{30}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-14\sqrt{30}}{2*49}=\frac{0-14\sqrt{30}}{98}
=-\frac{14\sqrt{30}}{98}
=-\frac{\sqrt{30}}{7}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+14\sqrt{30}}{2*49}=\frac{0+14\sqrt{30}}{98}
=\frac{14\sqrt{30}}{98}
=\frac{\sqrt{30}}{7}
$