Which statement is correct about the values of x and y in the following equation?
7x+xy = xy+21
a) the equation is true for all ordered pairs (x, y)
b) there are no (x, y) pairs for which this equation is true.
c) for each value of x, there is one and only one value of y that makes the equation true.
d) for each value of y, there is one and only value of x that makes the equation true.

The number of chocolate chips in an 18-ounce bag of chocolate chip cookies is approximately normally distributed with a mean of 1252 chips and standard deviation 129 chips. (a) what is the probability that a randomly selected bag contains between 1100 and 1500 chocolate chips, inclusive? (b) what is the probability that a randomly selected bag contains fewer than 1125 chocolate chips? (c) what proportion of bags contains more than 1225 chocolate chips? (d) what is the percentile rank of a bag that contains 1425 chocolate chips?

List the sides of δrst in ascending order (shortest to longest) if: m∠r =x+28°, m∠s = 2x+16°, and m∠t = x+12

How many verticies does a triangular prims have