5a2-7=5

Solution for 5a2-7=5 equation:

5a^2-7=5

We move all terms to the left:

5a^2-7-(5)=0

We add all the numbers together, and all the variables

5a^2-12=0

a = 5; b = 0; c = -12;
Δ = b2-4ac
Δ = 02-4·5·(-12)
Δ = 240
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{240}=\sqrt{16*15}=\sqrt{16}*\sqrt{15}=4\sqrt{15}$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{15}}{2*5}=\frac{0-4\sqrt{15}}{10}
=-\frac{4\sqrt{15}}{10}
=-\frac{2\sqrt{15}}{5}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{15}}{2*5}=\frac{0+4\sqrt{15}}{10}
=\frac{4\sqrt{15}}{10}
=\frac{2\sqrt{15}}{5}
$