How do you solve the system x = 5 - y and 3y = 3x + 1 by substitution?

1 Answer
May 28, 2015

We can substitute the x of the first equation into the second:

->3y=3*(5-y)+1
->3y=15-3y+1
->6y=16->y=16/6=8/3

Now plug that into the first equation:
x=5-8/3 =15/3-8/3=7/3

So x=7/3 and y=8/3

Check your answer with the second equation:

3* 8/3 = 3* 7/3 +1 ?-> 8=7+1 Check!