90=s+89

Solution for 90=s+89 equation:

Simplifying
90 = s + 89

Reorder the terms:
90 = 89 + s

Solving
90 = 89 + s

Solving for variable 's'.

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

Add '-1s' to each side of the equation.
90 + -1s = 89 + s + -1s

Combine like terms: s + -1s = 0
90 + -1s = 89 + 0
90 + -1s = 89

Add '-90' to each side of the equation.
90 + -90 + -1s = 89 + -90

Combine like terms: 90 + -90 = 0
0 + -1s = 89 + -90
-1s = 89 + -90

Combine like terms: 89 + -90 = -1
-1s = -1

Divide each side by '-1'.
s = 1

Simplifying
s = 1