Answer: r = 9
Explanation:
Simplifying
20 = r + 11
Reorder the terms:
20 = 11 + r
Solving
20 = 11 + 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.
20 + -1r = 11 + r + -1r
Combine like terms: r + -1r = 0
20 + -1r = 11 + 0
20 + -1r = 11
Add '-20' to each side of the equation.
20 + -20 + -1r = 11 + -20
Combine like terms: 20 + -20 = 0
0 + -1r = 11 + -20
-1r = 11 + -20
Combine like terms: 11 + -20 = -9
-1r = -9
Divide each side by '-1'.
r = 9
Simplifying
r = 9