8.1r-(1+8r)=-1.8

Solution for 8.1r-(1+8r)=-1.8 equation:

Simplifying
8.1r + -1(1 + 8r) = -1.8
8.1r + (1 * -1 + 8r * -1) = -1.8
8.1r + (-1 + -8r) = -1.8

Reorder the terms:
-1 + 8.1r + -8r = -1.8

Combine like terms: 8.1r + -8r = 0.1r
-1 + 0.1r = -1.8

Solving
-1 + 0.1r = -1.8

Solving for variable 'r'.

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

Add '1' to each side of the equation.
-1 + 1 + 0.1r = -1.8 + 1

Combine like terms: -1 + 1 = 0
0 + 0.1r = -1.8 + 1
0.1r = -1.8 + 1

Combine like terms: -1.8 + 1 = -0.8
0.1r = -0.8

Divide each side by '0.1'.
r = -8

Simplifying
r = -8