The equation 3i + 2i - 7 = 18 is simplified as 5i - 7 = 18.
To isolate i, we add 7 to both sides:
5i - 7 + 7 = 18 + 7
5i = 25
Then, we divide both sides by 5:
5i/5 = 25/5
i = 5
Therefore, the solution to the equation 3i + 2i - 7 = 18 is i = 5.