20=-8a+9a

Solution for 20=-8a+9a equation:

Simplifying
20 = -8a + 9a

Combine like terms: -8a + 9a = 1a
20 = 1a

Solving
20 = 1a

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.
20 + -1a = 1a + -1a

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

Add '-20' to each side of the equation.
20 + -20 + -1a = 0 + -20

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

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

Divide each side by '-1'.
a = 20

Simplifying
a = 20