7x2=51

Solution for 7x2=51 equation:

7x^2=51

We move all terms to the left:

7x^2-(51)=0

a = 7; b = 0; c = -51;
Δ = b2-4ac
Δ = 02-4·7·(-51)
Δ = 1428
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:

$\sqrt{\Delta}=\sqrt{1428}=\sqrt{4*357}=\sqrt{4}*\sqrt{357}=2\sqrt{357}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{357}}{2*7}=\frac{0-2\sqrt{357}}{14}
=-\frac{2\sqrt{357}}{14}
=-\frac{\sqrt{357}}{7}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{357}}{2*7}=\frac{0+2\sqrt{357}}{14}
=\frac{2\sqrt{357}}{14}
=\frac{\sqrt{357}}{7}
$