Math help please
posted by Charlotte .
1. The ordered pairs (1, 1), (2, 8), (3, 27), (4, 64), and (5,125) represent a function. What is a rule that represents this function?
Y = x
Y = 4x
Y = x^2
Y = x^3
I don't know how to solve this please help!
The easy way to do these is to look at it and try each of the answers.
For example, 2*1 is not 8 for a answer.
2*4 is 8 and that's ok but 3*4 is not 27.
For answer c, 2^2 = 4 and that's not ok.
Finally, 2*^3 = 8 which is ok. Next, 3^3 = 27 and that's ok. Next 4^3 = 64 and that's ok so I'd go with y = x^3. You can check out the last ordered pair to make sure 5^3 = 125.
Well for this problem what you would do is you would take each set of ordered pairs and substitute the x coordinate for x and the y coordinate for y.
If for all 5 ordered pairs a function works, then that is your answer.
For example take the first one.
With the set of coordinates (1,1)...
the first function would work because 1=1.
Lets try substituting another pair for the same function. (2,8)
Since that is not true, you know that this function is not true for all the ordered pairs.
Try this method for the rest of the functions. I hope this helps!