Answer:
(C)
Step-by-step explanation:
Plug in 1 for s, and 2 for t:
5t - 2 = 5(2) - 2 = 10 - 2 = 8
t + 6 = (2) + 6 = 8
2s + 3 = 2(1) + 3 = 2 + 3 = 5
3s + 2 = 3(1) + 2 = 3 + 2 = 5
NM = PO = 8 ; NO = MP = 5 ∴ (C) is your answer
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You have 10 numbers to choose from, and you're choosing 4 from that pool. Order of the numbers matters, because having 1234 as a PIN is not the same having it be 1324, so we're counting the number of permutations of 10 digits taken 4 at a time. So there are

possible PINs that can be made.
SRT = 20 => STR = 20.
Since STR and STU are supplementary angles, STU = 180 - STR = 180 - 20 = 160, means x = 40.
Replace x with a couple of numbers, solve for Y them mark those points on the graph and connect with a line.
See picture: