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Melanie is trying to graph x = 4. She says that her line will go from side to side and have an undefined slope. Andrea says, " Uh no, I think you're wrong. It's supposed to go up and down and have a slope of 0." Explain how one of them is correct or wrong.
Melanie's right because the slope is undefined, but wrong because it's supposed to go up and down. Andrea is right about it going up and down, but wrong about the slope.