21=8x+6-1

Solution for 21=8x+6-1 equation:

Simplifying
21 = 8x + 6 + -1

Reorder the terms:
21 = 6 + -1 + 8x

Combine like terms: 6 + -1 = 5
21 = 5 + 8x

Solving
21 = 5 + 8x

Solving for variable 'x'.

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

Add '-8x' to each side of the equation.
21 + -8x = 5 + 8x + -8x

Combine like terms: 8x + -8x = 0
21 + -8x = 5 + 0
21 + -8x = 5

Add '-21' to each side of the equation.
21 + -21 + -8x = 5 + -21

Combine like terms: 21 + -21 = 0
0 + -8x = 5 + -21
-8x = 5 + -21

Combine like terms: 5 + -21 = -16
-8x = -16

Divide each side by '-8'.
x = 2

Simplifying
x = 2