a+b = 65
b - 2a = 5
Solve one variable in terms of another:
b = 5 + 2a
Substitute in this variable:
a + 5 + 2a = 65
3a = 70
a = 23.3
Use this to find the other variable:
23.3 + b = 65
b = 41.7
Check the answer:
23.3 + 41.7 = 65
65 = 65
ANSWERS:
a = 23.3
b = 41.7