Categories

# “Graph x = 3”

The mistake is pretty easy. But what’s the underlying misconception?

## 8 replies on ““Graph x = 3””

Michael Psays:

There’s also a juicy little bonus mistake in #6.

GroshongMarysays:

Looks to me like the student doesn’t understand that X=3 is a line, since ther is no y mentioned.As for number six, the student counted the xs in the problem, separated them by +signs, and called it good. No good understanding that factors are things to be multiplied perhaps? I’d say a basic misunderstanding of factoring.

John Burksays:

I think it’s interesting that the student had also colored in the points (0,3) and (3,3), and then erased those two choices. So first this might be some confusion as to the whole idea of an axes, and what the x-axis is.

Michael Psays:

Underneath it all there’s a bit problem with this kid’s understanding of equations and coordinates. It should be impossible to put that point down without knowing a corresponding y coordinate. Maybe what could help would be an activity where the student shades in points that fulfill a condition. For example, “Find all the points that are two units away from the origin,” “Find all the points where x = 3”, and “Find all the points where x =3 and y = 2.”

Gary Pococksays:

Student: Last week, when you asked us to graph the solution of 2x – 1 = 5, the answer was just a point. Teacher: Yes, but this question is asking you to plot all the points on the plane with an x-value of 3.Student: *sigh* THEN WHY DON’T YOU SAY SO?! You math teachers speak another language.

Barry Smithsays:

Conversation from a parallel universe:Student: Last week, when you asked us to graph the solution of 2x – 1 = 5, the answer was just a point.Teacher: But you might recall that the picture was much simpler last week. We simply drew a line and plotted a point on it. It is hard to miss the huge grid in this problem. How did you decide where to place the point?Student: Well, you told us the x-axis was that horizontal one running through the middle, and since it said “x=3”, I decided to put the point on the x-axis.

maxmathforumsays: