It has been a while since I have had to do algebra homework but with a student in 8th grade I am learning again! Last night we had an argument (again!) about homework. She is graphing equations using y=mx+b. For a few of the problems she was getting a fraction for the b part and insisted that that could not be graphed. So our question is, "How do you graph a fraction?" Thank you!
If I remember right, the 'b' is for the y-intercept, correct? If so, you would just graph it accordingly (as on a number line). So, 1/2 would be halfway between 0 and 1. If she's using grid paper, she could even make a scale where each square equals 1/2.
Don't you just graph it like you would graph a whole number? Like, there's all that space between the lines on the graph paper, so that would be the fractions, right?
I thought you would just graph it like a whole number but she is not sure and doesn't want to be wrong. She is going to ask her teacher to clarify but I wanted to know as well. Thanks for the quick replies!!!!
Depending on the fraction and the scale, you could even set the boxes differently -- so, if your fraction is one half, mark "one" after two boxes, and then your graph paper line gives you the exact halfway point. Just be sure to do the same on the x-axis.
If the fraction is in the m part of y = mx +b , then treat it as rise over run. Example, if the function is y = 2/3 x + b, then go up 2, over 3 for the slope. If the fraction is in the place of the b (which, yes, is the y-intercept), find where that fraction would fall on the y-axis, graph that point, then continue on as normal for whatever the slope is.
Very often, when the y-intercept is a fraction, I tell my kids to guestimate its value. Then, as others have said, use rise/run. You'll end up getting a few other fractions, but that's OK Alternately, she can simply do the problem another way. Have her choose ANY 3 values for x, one at a time. (I usually choose 0, 1, and 2.) Plug them into the problem, and you'll get the corresponding y values. Each x and y pair combine to give you a point on the line. so if the equation is y = 2x - 1/2 I get (0, -1/2) (1, 1.5) (2, 3.5) Plot the 3 points, connect them, put on your arrows and label the graph, and you're good to go.
She could also revise the graphing paper so that every two lines equals one. Then 1/2 would be on a line. Or just use bigger graph paper so you can easily see where 1/2 would fall on the axis.
I use google to help me find those types of answers! A couple of times I've even have found the actual worksheet with answers. I have to be able to work the problem before I explain it to my son. So, I'm checking my answer, so that I can help answer his questions.
Thank you to everyone for replying! I tried google for the worksheet and just a general search on y intercept but was not successful. I knew that a to z was the place to go! Her teacher did tell her to graph the y intercept as a fraction and estimate where it should go. I don't know what I am going to do when she gets past geometry...
My son took honors geo last year. This year he'll have Alg. 2. Then I'm not for sure what. He's on track for an AP math class. This year he's taking Chemistry! I've never had Chem. Thankfully, right now it's stuff I learned in Bio.
