42=3(-14r)

Solution for 42=3(-14r) equation:

Simplifying
42 = 3(-14r)

Remove parenthesis around (-14r)
42 = 3 * -14r

Multiply 3 * -14
42 = -42r

Solving
42 = -42r

Solving for variable 'r'.

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

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

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

Add '-42' to each side of the equation.
42 + -42 + 42r = 0 + -42

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

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

Divide each side by '42'.
r = -1

Simplifying
r = -1