Answer: Jacob is 7 years old.
Step-by-step explanation: 5 years ago, Jacob was 2 years old and his brother was 12. Now, in three years, Jacob will be 10 and his brother will be 20. To find the answer, you need a system of equations. The first equation will be 6(J-5) = B - 5, where J is Jacob's current age and B is his brother's. The next equation will be 2(J + 3) = B + 3. Now, just solve the equation. I gave you the answer, but please work through the problem so you understand it :D
