Declare variables for each age:

- Let Casey's age be c
- Let her daughter's age be d
- Let n be the number of years from now where Casey will be double her daughter's age

26 + n = 2(4 + n)

26 + n = 8 + 2n

Solve for

*n*in the equation 26 + n = 8 + 2n

**Step 1: Group variables:**

We need to group our variables n and 2n. To do that, we subtract 2n from both sides

n + 26 - 2n = 2n + 8 - 2n

**Step 2: Cancel 2n on the right side:**

-n + 26 = 8

**Step 3: Group constants:**

We need to group our constants 26 and 8. To do that, we subtract 26 from both sides

-n + 26 - 26 = 8 - 26

**Step 4: Cancel 26 on the left side:**

-n = -18

**Step 5: Divide each side of the equation by -1**

-1n/-1 = -18/-1

n =

**18**

Check our work for n = 18:

26 + 18 ? 8 + 2(18)

44 ? 8 + 36

44 = 44