r+3+2r+6+r=57

Solution for r+3+2r+6+r=57 equation:

Simplifying
r + 3 + 2r + 6 + r = 57

Reorder the terms:
3 + 6 + r + 2r + r = 57

Combine like terms: 3 + 6 = 9
9 + r + 2r + r = 57

Combine like terms: r + 2r = 3r
9 + 3r + r = 57

Combine like terms: 3r + r = 4r
9 + 4r = 57

Solving
9 + 4r = 57

Solving for variable 'r'.

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

Add '-9' to each side of the equation.
9 + -9 + 4r = 57 + -9

Combine like terms: 9 + -9 = 0
0 + 4r = 57 + -9
4r = 57 + -9

Combine like terms: 57 + -9 = 48
4r = 48

Divide each side by '4'.
r = 12

Simplifying
r = 12