2x*x-5=12

Solution for 2x*x-5=12 equation:

2x*x-5=12

We move all terms to the left:

2x*x-5-(12)=0

We add all the numbers together, and all the variables

2x*x-17=0

Wy multiply elements

2x^2-17=0

a = 2; b = 0; c = -17;
Δ = b2-4ac
Δ = 02-4·2·(-17)
Δ = 136
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:

$\sqrt{\Delta}=\sqrt{136}=\sqrt{4*34}=\sqrt{4}*\sqrt{34}=2\sqrt{34}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{34}}{2*2}=\frac{0-2\sqrt{34}}{4}
=-\frac{2\sqrt{34}}{4}
=-\frac{\sqrt{34}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{34}}{2*2}=\frac{0+2\sqrt{34}}{4}
=\frac{2\sqrt{34}}{4}
=\frac{\sqrt{34}}{2}
$