Is the following relation a function, yes or no?
{(3,2.1),(4,3.1), (5,2.7), (5, 4.1), (6,5.1)}

Which composition of similarity transformations maps polygon abcd to polygon a'b'c'd'? a dilation with a scale factor less than 1 and then a reflection a dilation with a scale factor less than 1 and then a translation a dilation with a scale factor greater than 1 and then a reflection a dilation with a scale factor greater than 1 and then a translation

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?

Give me the equations of two lines that have the same slope but are not parallel.