140=a-20

Solution for 140=a-20 equation:

Simplifying
140 = a + -20

Reorder the terms:
140 = -20 + a

Solving
140 = -20 + 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.
140 + -1a = -20 + a + -1a

Combine like terms: a + -1a = 0
140 + -1a = -20 + 0
140 + -1a = -20

Add '-140' to each side of the equation.
140 + -140 + -1a = -20 + -140

Combine like terms: 140 + -140 = 0
0 + -1a = -20 + -140
-1a = -20 + -140

Combine like terms: -20 + -140 = -160
-1a = -160

Divide each side by '-1'.
a = 160

Simplifying
a = 160