-3(r+7)=-57

Solution for -3(r+7)=-57 equation:

Simplifying
-3(r + 7) = -57

Reorder the terms:
-3(7 + r) = -57
(7 * -3 + r * -3) = -57
(-21 + -3r) = -57

Solving
-21 + -3r = -57

Solving for variable 'r'.

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

Add '21' to each side of the equation.
-21 + 21 + -3r = -57 + 21

Combine like terms: -21 + 21 = 0
0 + -3r = -57 + 21
-3r = -57 + 21

Combine like terms: -57 + 21 = -36
-3r = -36

Divide each side by '-3'.
r = 12

Simplifying
r = 12