Question 252993
Let x=smaller number; 2x=smaller number doubled
Then 39-x=larger number; 39-x+3=42-x=larger number increased by 3

Now we are told that 2x=42-x add x to each side

3x=42
x=14---------smaller number
39-x=39-14=25----larger number

CK
2*14=25+3
28=28

We can also solve this using two unknowns:
x=smaller number
y=larger number
x+y=39---------------------eq1
and
2x=y+3-----------------------eq2
From eq2, y=2x-3; substitute this into eq1
x+2x-3=39 add three to both sides
3x=42 same as before

Hope this helps----ptaylor