Four times the sum of a number x and a number y is equal to 20.

Sure, I can help with that. Here's how you can solve the problem:

Step 1: Translate the problem into a mathematical equation. The problem states "Four times the sum of a number x and a number y is equal to 20." This can be written as 4*(x + y) = 20.

Step 2: Simplify the equation. Distribute the 4 to both x and y to get 4x + 4y = 20.

Step 3: Solve for one of the variables. If you want to solve for x, you can subtract 4y from both sides to get 4x = 20 - 4y.

Step 4: Divide both sides by 4 to isolate x. This gives you x = 5 - y.

This is your solution in terms of y. If you have a specific value for y, you can substitute it into this equation to find the corresponding value of x. Similarly, you can solve for y in terms of x using the same steps.