State the domain and range of the following function

What should be done to solve the equation? x+14=21 add 14 to both sides of the equation. subtract 14 from the left side of the equation. add 14 to the left side and subtract 14 from the right side of the equation. subtract 14 from both sides of the equation.

You paint a 1/2 of a wall in 1/4 hour. how long will it take you to paint one wall

How do you use the elimination method for this question? explain, because i really want to understand!