9(1+9r)-7(2r+2)=-72

Solution for 9(1+9r)-7(2r+2)=-72 equation:

Simplifying
9(1 + 9r) + -7(2r + 2) = -72
(1 * 9 + 9r * 9) + -7(2r + 2) = -72
(9 + 81r) + -7(2r + 2) = -72

Reorder the terms:
9 + 81r + -7(2 + 2r) = -72
9 + 81r + (2 * -7 + 2r * -7) = -72
9 + 81r + (-14 + -14r) = -72

Reorder the terms:
9 + -14 + 81r + -14r = -72

Combine like terms: 9 + -14 = -5
-5 + 81r + -14r = -72

Combine like terms: 81r + -14r = 67r
-5 + 67r = -72

Solving
-5 + 67r = -72

Solving for variable 'r'.

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

Add '5' to each side of the equation.
-5 + 5 + 67r = -72 + 5

Combine like terms: -5 + 5 = 0
0 + 67r = -72 + 5
67r = -72 + 5

Combine like terms: -72 + 5 = -67
67r = -67

Divide each side by '67'.
r = -1

Simplifying
r = -1