There are two unknowns in this problem. To start, let's assign variables to each of them. Let x be the age of Jacob and y be the age of Isaiah. Then, we formulate equations based on the relationships stated.
x = 7 + y --> eqn 1
x + y = 63 --> eqn 2
Substituting eqn 1 to eqn 2, then solve for x and y:
(7+y)+y = 63
7 + 2y = 63
2y = 63 - 7
2y = 56
y = 56/2
y = 28
x = 28 + 7 = 35
Therefore, Jacob is 35 years old, and Isaiah is 28 years old.