.20x+.05(12-x)=.10(9)

Solution for .20x+.05(12-x)=.10(9) equation:

Simplifying
0.20x + 0.05(12 + -1x) = 0.10(9)
0.20x + (12 * 0.05 + -1x * 0.05) = 0.10(9)
0.20x + (0.6 + -0.05x) = 0.10(9)

Reorder the terms:
0.6 + 0.20x + -0.05x = 0.10(9)

Combine like terms: 0.20x + -0.05x = 0.15x
0.6 + 0.15x = 0.10(9)

Multiply 0.10 * 9
0.6 + 0.15x = 0.9

Solving
0.6 + 0.15x = 0.9

Solving for variable 'x'.

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

Add '-0.6' to each side of the equation.
0.6 + -0.6 + 0.15x = 0.9 + -0.6

Combine like terms: 0.6 + -0.6 = 0.0
0.0 + 0.15x = 0.9 + -0.6
0.15x = 0.9 + -0.6

Combine like terms: 0.9 + -0.6 = 0.3
0.15x = 0.3

Divide each side by '0.15'.
x = 2

Simplifying
x = 2