18=3+r

Solution for 18=3+r equation:

Simplifying
18 = 3 + r

Solving
18 = 3 + r

Solving for variable 'r'.

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

Add '-1r' to each side of the equation.
18 + -1r = 3 + r + -1r

Combine like terms: r + -1r = 0
18 + -1r = 3 + 0
18 + -1r = 3

Add '-18' to each side of the equation.
18 + -18 + -1r = 3 + -18

Combine like terms: 18 + -18 = 0
0 + -1r = 3 + -18
-1r = 3 + -18

Combine like terms: 3 + -18 = -15
-1r = -15

Divide each side by '-1'.
r = 15

Simplifying
r = 15