7u^2+21=77

Solution for 7u^2+21=77 equation:

Simplifying
7u2 + 21 = 77

Reorder the terms:
21 + 7u2 = 77

Solving
21 + 7u2 = 77

Solving for variable 'u'.

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

Add '-21' to each side of the equation.
21 + -21 + 7u2 = 77 + -21

Combine like terms: 21 + -21 = 0
0 + 7u2 = 77 + -21
7u2 = 77 + -21

Combine like terms: 77 + -21 = 56
7u2 = 56

Divide each side by '7'.
u2 = 8

Simplifying
u2 = 8

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