Here are two rules that you should memorize and/or write down in your notebook somewhere (or perhaps put it on a flashcard)
Rule #1: If the slopes of two lines are the same, but the y intercepts are different, then the two lines are parallel.
Rule #2: If the slope of the two lines multiply to -1, then the lines are perpendicular.
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For problem 66, we see that the slopes 1/4 and 4 are not the same, and they also don't multiply to -1. One slope would have to be negative and the other positive for this happen. Therefore the answer to problem 66 is "neither"
The answer to problem 68 is "perpendicular" because the two slopes -4/5 and 5/4 multiply to -1 (we are using rule #2 in this case). One number is the negative reciprocal of the other. Basically you flip the fraction and flip the sign to go from -4/5 to 5/4 (or vice versa).