Means, for every 1 input, there is 1 coresponding output
normally x is input and y is output in form (x,y)
so just look for the option(s) that has/have every first number repeat with only 1 2nd number
A. -7 repeats with 5 and -3, not a function
B. no repeats of first number (6,-8) and (-5,-8) are fine because first numbers don't repeat, das is funciton
C. no repeats, function
D. no repeats, function
answer is B,C,D
A= 6x4=24+70= $94
B=6x5=30+60=$90
So if you rented a truck for 6 hours, you are saving $4 by using Company B.
A=4x7=28+70=$98
B=5x7=35+60=$95
So if you rent a truck for 7 hours, Company B would save you $3.
Infinitely many is the correct answer
At least 26 questions to get around an 82% not 25 because that equals 78%