A student does this. How would you respond? (Multiple ideas welcome!) pic.twitter.com/SzWzuFfQmn

— Michael Fenton (@mjfenton) June 10, 2016

Lots of responses to this great tweet. I wanted to understand the themes in what people were replying, so I went through everything and tried to summarize it here.

**Response #1: Check Your Work, Start a Conversation**

@mjfenton tell them to plug back in and defend their answer. Start a dialogue about the role of factoring in the solution. Why do it at all?

— Eric Fleming (@dailyvalueomath) June 10, 2016

@mjfenton I'd ask them to verify their answer and see what they get, then use that moment of cog-dissonance to develop 0-prod prop

— Daniel Schneider (@MathyMcMatherso) June 10, 2016

**Response #2: Just Check Your Work (No Conversation Mentioned in Tweet)**

@mjfenton @Thalesdisciple Remind them to check their proposed answer by plugging it back into the original problem and see if it works.

— Dan Hagon (@axiomsofchoice) June 10, 2016

@mjfenton maybe try to have them plug in their solutions and see if they work.

— Kathy H (@kathyhenderson) June 10, 2016

@mjfenton @mpershan Have them plug in to check… but plug in factored form, not original problem.

— Samuel Otten (@ottensam) June 10, 2016

**Response #3: Explain the Zero Product Property**

@mjfenton @mpershan The reason we factor is that there's a special rule when the product is zero

There's no rule for product of 2.— Chris Burke (@mrburkemath) June 10, 2016

@mjfenton I'd talk about why there is no one-product property, or two-product, only a zero product

— Brian Miller (@TheMillerMath) June 10, 2016

@mjfenton Students can then realize just because two factors * to 2 doesn't imply either factor could be 2. Only works if product = 0.

— Tim Brzezinski (@dynamic_math) June 10, 2016

**Response #4: Thinking About How to Teach the ZPP Unit**

@mjfenton When I teach ZPP I start with a game. Ab=1. If you guess a and b you win $20. I would remind them of this activity. A=sqrt(91)/e

— Thomas Totushek (@TheMathProphet) June 10, 2016

@mjfenton my team dvlpd lesson investigating this; Ss concluded easier if = 0 even tho cld b solvd; 1st yr ever taught truly conceptually

— Phillip H-H (@philliphsquared) June 10, 2016

@mjfenton possibly turn it into a systems of eqs prob. I'd also rethink how I taught the ZPP

— Amanda Sinner (@avsinner) June 10, 2016

@mjfenton Use a more extreme example with a clear "right" answer. CME book uses (x+7)(x+11) = 77.

— Bowen Kerins (@bowenkerins) June 10, 2016

**Response #5: Switch to a Graphical Context**

@mjfenton Look at a graphical representation of the original equation. https://t.co/H0QY8c0HSt

— Chris Bolognese (@EulersNephew) June 10, 2016

@mjfenton "Why aren't both of the blue points on the parabola?" pic.twitter.com/zVsC62myZU

— Christopher (@Trianglemancsd) June 10, 2016

@mjfenton Love this mistake. I would put it on @Desmos, then add the equation set equal to zero, discuss.

— Julie (@jreulbach) June 10, 2016

**Response #6: Ask for Explanations**

@mjfenton @Thalesdisciple ASK why line three follows from line two. Wait for response.

Each step has a meaning. The stu is missing that.

— TJ Hitchman (@ProfNoodlearms) June 10, 2016

@mjfenton maybe an algebraic proof… ask what math "rule" allows for line 3??

Or go there with the language and vocabulary+— Madelyne Bettis (@Mrs_Bettis) June 10, 2016

**Response #7: Run a New Activity with the Whole Class**

@mjfenton A my favorite no? Present it to the class for ideas.

— Teresa (Teri) Ryan (@geometrywiz) June 10, 2016

I’m sure I didn’t capture everyone’s response, and I don’t know what any of this means. But there you go.