21+56=k

Solution for 21+56=k equation:

Simplifying
21 + 56 = k

Combine like terms: 21 + 56 = 77
77 = k

Solving
77 = k

Solving for variable 'k'.

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

Add '-1k' to each side of the equation.
77 + -1k = k + -1k

Combine like terms: k + -1k = 0
77 + -1k = 0

Add '-77' to each side of the equation.
77 + -77 + -1k = 0 + -77

Combine like terms: 77 + -77 = 0
0 + -1k = 0 + -77
-1k = 0 + -77

Combine like terms: 0 + -77 = -77
-1k = -77

Divide each side by '-1'.
k = 77

Simplifying
k = 77