14r^2-21=0

Solution for 14r^2-21=0 equation:

Simplifying
14r2 + -21 = 0

Reorder the terms:
-21 + 14r2 = 0

Solving
-21 + 14r2 = 0

Solving for variable 'r'.

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

Add '21' to each side of the equation.
-21 + 21 + 14r2 = 0 + 21

Combine like terms: -21 + 21 = 0
0 + 14r2 = 0 + 21
14r2 = 0 + 21

Combine like terms: 0 + 21 = 21
14r2 = 21

Divide each side by '14'.
r2 = 1.5

Simplifying
r2 = 1.5

Take the square root of each side:
r = {-1.224744871, 1.224744871}