-7a^2=-63

Solution for -7a^2=-63 equation:

-7a^2=-63

We move all terms to the left:

-7a^2-(-63)=0

We add all the numbers together, and all the variables

-7a^2+63=0

a = -7; b = 0; c = +63;
Δ = b2-4ac
Δ = 02-4·(-7)·63
Δ = 1764
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1764}=42$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-42}{2*-7}=\frac{-42}{-14}
=+3
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+42}{2*-7}=\frac{42}{-14}
=-3
$