4=x^2-16

Solution for 4=x^2-16 equation:

Simplifying
4 = x2 + -16

Reorder the terms:
4 = -16 + x2

Solving
4 = -16 + x2

Solving for variable 'x'.

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

Add '-1x2' to each side of the equation.
4 + -1x2 = -16 + x2 + -1x2

Combine like terms: x2 + -1x2 = 0
4 + -1x2 = -16 + 0
4 + -1x2 = -16

Add '-4' to each side of the equation.
4 + -4 + -1x2 = -16 + -4

Combine like terms: 4 + -4 = 0
0 + -1x2 = -16 + -4
-1x2 = -16 + -4

Combine like terms: -16 + -4 = -20
-1x2 = -20

Divide each side by '-1'.
x2 = 20

Simplifying
x2 = 20

Take the square root of each side:
x = {-4.472135955, 4.472135955}