Answer:
Maggie is seven years old
Explanation:
Maggie's Brothers Age = B
Maggie's Age = M
2M - 4 = B
B + M = 17
Plug in 2M - 4 for B
( 2M - 4 ) + M = 17
Combine Like Terms
3M - 4 = 17
Add 4 to either side
3M = 21
Divide either side by 3
M = 7
Check your answer
2M - 4 = B -> 2 x 7 - 4 = B -> 14 -4 = B -> B = 10
B + M = 17 => 7 + 10 = 17 => 17 = 17