You can call the unknown numbers a and b
given:
(1) 2a+=+b+%2B+1
(2) a+%2B+b+=+5
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I want to get a and b both on the left side
Subtract b from both sides of (1)
2a+-+b+=+1
a+%2B+b+=+5
Now all you have to do is add the equations
3a+=+6
a+=+2
Substitute this in (2)
(2) a+%2B+b+=+5
2+%2B+b+=+5
b+=+3
The numbers are 2 and 3
