[tex]x + y = 49 \\ x + 2y = 70[/tex]
[tex]x = 49 - y[/tex]
Substitute that into,
[tex]49 - y + 2y = 70 \\ y = 21[/tex]
Substitute that into,
[tex]x = 49 - 21 \\ x = 28[/tex]
Answer check :
[tex]21 + 28 = 49 \\ 28 + 2(21) = 28 + 42 = 70[/tex]
Answer : The numbers are 21 and 28.
Hope this helps. - M
