Home > Math Group > Question and Answer

Math Group

Question:

loveetteee
loveetteee
Student

If y-3=7 and x+3y=6 then x=?

Show your work.

Rate question:

Posted by loveetteee on Thursday May 28, 2009 at 1:03 PM and tagged with algebra, solving equations.

Answers:


  1. jlcannad Teacher
    High School - 12th Grade

    eNotes Editor

    I can't answer x+3y=6 right now.  I have two variables (x and Y) so I'm stuck.

    So, I turn to my other equation.  y-3=7.  If I add three to each side of the equation, I get y=10.

    Now that I know y=10, I can put the number 10 in every place there was a "y."  So, the second equation looks like this...

    x+3y=6

    x+3(10)=6

    x+30=6      So I subtract 30 from each side.

    x=-24

     

    I then check myself by putting all my numbers back into the original equations.

    10-3=7 and -24+3(10)=6

    Yep, that works.

     

    Rate answer:

    Posted by jlcannad on Thursday May 28, 2009 at 1:10 PM

  2. emplay
    emplay Student
    High School - 11th Grade

    Well

    x+3y=6   and y-3=7

    (+3)y-3=7(+3)

    y=10

     

    x+3(10)=6

    x+30=6

    x= -24

    Rate answer:

    Posted by emplay on Thursday May 28, 2009 at 1:13 PM