3(2-r)=42-7r

Solution for 3(2-r)=42-7r equation:

Simplifying
3(2 + -1r) = 42 + -7r
(2 * 3 + -1r * 3) = 42 + -7r
(6 + -3r) = 42 + -7r

Solving
6 + -3r = 42 + -7r

Solving for variable 'r'.

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

Add '7r' to each side of the equation.
6 + -3r + 7r = 42 + -7r + 7r

Combine like terms: -3r + 7r = 4r
6 + 4r = 42 + -7r + 7r

Combine like terms: -7r + 7r = 0
6 + 4r = 42 + 0
6 + 4r = 42

Add '-6' to each side of the equation.
6 + -6 + 4r = 42 + -6

Combine like terms: 6 + -6 = 0
0 + 4r = 42 + -6
4r = 42 + -6

Combine like terms: 42 + -6 = 36
4r = 36

Divide each side by '4'.
r = 9

Simplifying
r = 9