21+8x+(-15)=

Solution for 21+8x+(-15)= equation:

Simplifying
21 + 8x + (-15) = 0
21 + 8x + -15 = 0

Reorder the terms:
21 + -15 + 8x = 0

Combine like terms: 21 + -15 = 6
6 + 8x = 0

Solving
6 + 8x = 0

Solving for variable 'x'.

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

Add '-6' to each side of the equation.
6 + -6 + 8x = 0 + -6

Combine like terms: 6 + -6 = 0
0 + 8x = 0 + -6
8x = 0 + -6

Combine like terms: 0 + -6 = -6
8x = -6

Divide each side by '8'.
x = -0.75

Simplifying
x = -0.75