<PRE><B>Question 883725</B>
A + B = 99
A - 2B = 15
Use the second equation and add 2B to each side to get:
A = 2B + 15
Now substitute the value of A from that equation into the first equation:
A + B = 99
(2B + 15) + B = 99
Add
3B + 15 = 99
Subtract 15 from each side
3B = 84
Divide each side by 3
B = 28
If B is 28, then A is 99-28, or 71
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