Problem 18
The x should not be in the denominator. If it was in the denominator, then you wouldn't have a linear equation in the form y = mx+b
Instead, you should have written
or y = (1/17)x + 63/17
Comparing that to y = mx+b form, we see that m = 1/17 is the slope and b = 63/17 is the y intercept.
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Problem 19
This problem isn't fully shown. The right portion is cut off. I have a feeling the same issue is happening here though. Try moving the x term like mentioned in problem 18. Also, don't forget about the "y=" portion.