You can solve this by substitution. Put the equation for y in place of y.
You can make [tex]x+3(2x+1)=31[/tex]
Multiply the [tex]3(2x+1) [/tex] out and get [tex]6x+3[/tex]
And the equation [tex]x+6x+3=31[/tex]
Add common factors and subtract the 3 over to the 31 and get
[tex]7x=28[/tex]
Finally, divide both sides by 7 and get x=4
Put the x in for the top equation and do [tex]2(4) + 1 =y[/tex]
Solve it and get y = 9
X=4
Y=9
