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I got the first one. For the second one, I got (1,3) and (1,-2). For the lines: 2x+1 and 2x-4. But I don't know if I did it correctly. Here's my work: large image
For C, I thought I needed to find when dy/dx does not exist, but I don't know what to do since there are two variables. I would guess one would be at 0, but I'm thinking there will be another point at which the tangent line is veritical.
Thank you so so so much in advance!