r^2+4-12=0

Solution for r^2+4-12=0 equation:

Simplifying
r2 + 4 + -12 = 0

Reorder the terms:
4 + -12 + r2 = 0

Combine like terms: 4 + -12 = -8
-8 + r2 = 0

Solving
-8 + r2 = 0

Solving for variable 'r'.

Move all terms containing r to the left, all other terms to the right.

Add '8' to each side of the equation.
-8 + 8 + r2 = 0 + 8

Combine like terms: -8 + 8 = 0
0 + r2 = 0 + 8
r2 = 0 + 8

Combine like terms: 0 + 8 = 8
r2 = 8

Simplifying
r2 = 8

Take the square root of each side:
r = {-2.828427125, 2.828427125}