Answer :
2n+5=x
n+x=35
n+x=35
x=35-n substitute into the other equation.
2n+5=x
2n+5=35-n
3n+5=35
3n=30
n=10
Go back to find x using your n value.
n+x=35
10+x=35
x=25
n+x=35
n+x=35
x=35-n substitute into the other equation.
2n+5=x
2n+5=35-n
3n+5=35
3n=30
n=10
Go back to find x using your n value.
n+x=35
10+x=35
x=25