r^2+4-16=0

Solution for r^2+4-16=0 equation:

Simplifying
r2 + 4 + -16 = 0

Reorder the terms:
4 + -16 + r2 = 0

Combine like terms: 4 + -16 = -12
-12 + r2 = 0

Solving
-12 + r2 = 0

Solving for variable 'r'.

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

Add '12' to each side of the equation.
-12 + 12 + r2 = 0 + 12

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

Combine like terms: 0 + 12 = 12
r2 = 12

Simplifying
r2 = 12

Take the square root of each side:
r = {-3.464101615, 3.464101615}