.25x+.15(4-x)=0.9(-1)

Solution for .25x+.15(4-x)=0.9(-1) equation:

Simplifying
0.25x + 0.15(4 + -1x) = 0.9(-1)
0.25x + (4 * 0.15 + -1x * 0.15) = 0.9(-1)
0.25x + (0.6 + -0.15x) = 0.9(-1)

Reorder the terms:
0.6 + 0.25x + -0.15x = 0.9(-1)

Combine like terms: 0.25x + -0.15x = 0.1x
0.6 + 0.1x = 0.9(-1)

Multiply 0.9 * -1
0.6 + 0.1x = -0.9

Solving
0.6 + 0.1x = -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 + 0.1x = -0.9 + -0.6

Combine like terms: 0.6 + -0.6 = 0.0
0.0 + 0.1x = -0.9 + -0.6
0.1x = -0.9 + -0.6

Combine like terms: -0.9 + -0.6 = -1.5
0.1x = -1.5

Divide each side by '0.1'.
x = -15

Simplifying
x = -15