# Problem 1 - Part A

## problem 1 - part a

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Students are presented with three possible ways to begin solving the problem, “Solve for x: 2x2-14x+20=0,” and asked to decide together which way(s) of starting the problem are correct.

## problem 1 - part a

Barbara Shreve, San Lorenzo High School, San Lorenzo Unified School District, San Leandro, California

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BARBARA SHREVE: I'm so proud of you, and thank you so much for being willing to do this because I get to be here with you guys and watch how hard you're working every day. And I'm excited about what we've accomplished this year as a group, and I'm looking forward to seeing what we still do in our last weeks together. Okay? So should we get back into some math? Good! You're going to need a clear, clear space. You can leave your notebook off to the side. If your backpack’s on the table, will you clear it because you're going to need to be able to work together with the person next to you.

So I have geometry students in other years, right? I don't have them this year, but one of the things I notice a lot is that when they go back to work on these quadratics, they forget sometimes how to start. So they had this problem like the ones you've been seeing, solve for x, where the equation is 2x2-14x+20=0. And three different people started that in different ways, and you can see that. I'm going to give you two minutes as a table to decide who is correct. So look at those three ways to start and you don't have to finish the problem, but whose first step makes sense? Okay? I already see table 6 leaning in to talk. Can you guys talk together, and in two minutes I'm going to ask you to decide as a table who is correct.

STUDENT: Hold on.

STUDENT: This is a, b, and c is 20 but...

STUDENT: Okay, that's right.

STUDENT: That's right and that's right.

STUDENT: Yeah, this is right.

STUDENT: This one?

STUDENT: Yeah.

STUDENT: Dulce, get me the list that’s right here.

STUDENT: This one?

STUDENT: Mm-hmm, but why do they give you all of the things correct?

STUDENT: Yes, but we need to find the value only of x [inaudible].

STUDENT: If we do this one, it's going to be like different answers. And if we do this one...

STUDENT: This is right?

STUDENT: Yeah. Because that's how it started off with.

STUDENT: Okay.