Seriously, just show her wolfram alpha. don't hide the good stuff away.
http://www.wolframalpha.com/input/?i=y+=+3x,+y+=+x,+y+=+1/2+x,+y+=+2x++5,+y+=+4x++2,+y+=+2x++4
It is like.. magic..
(it does everything else too, and let you in on how it solves it too). I used it to check my answers and if I was lost.
http://www.wolframalpha.com/input/?i=y+=+3x,+y+=+x,+y+=+1/2+x,+y+=+2x++5,+y+=+4x++2,+y+=+2x++4
It is like.. magic..
(it does everything else too, and let you in on how it solves it too). I used it to check my answers and if I was lost.