5x*x=720

Solution for 5x*x=720 equation:

5x*x=720

We move all terms to the left:

5x*x-(720)=0

Wy multiply elements

5x^2-720=0

a = 5; b = 0; c = -720;
Δ = b2-4ac
Δ = 02-4·5·(-720)
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-120}{2*5}=\frac{-120}{10}
=-12
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+120}{2*5}=\frac{120}{10}
=12
$