20 = r + 11

Solve the equation.

r=9

Step-by-step explanation:

Step 1: Flip the equation

r + 11 = 20

Step 2: Subtract 11 from both sides

r + 11 - 11 = 20 - 11

Answer: r = 9

Step-by-step 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