31=a-57

Solution for 31=a-57 equation:

Simplifying
31 = a + -57

Reorder the terms:
31 = -57 + a

Solving
31 = -57 + a

Solving for variable 'a'.

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

Add '-1a' to each side of the equation.
31 + -1a = -57 + a + -1a

Combine like terms: a + -1a = 0
31 + -1a = -57 + 0
31 + -1a = -57

Add '-31' to each side of the equation.
31 + -31 + -1a = -57 + -31

Combine like terms: 31 + -31 = 0
0 + -1a = -57 + -31
-1a = -57 + -31

Combine like terms: -57 + -31 = -88
-1a = -88

Divide each side by '-1'.
a = 88

Simplifying
a = 88