If P = 3x2 + xy - 5y? Q = 2x2 - xy + 3y2 and R = -6x2 + 4xy - 7y2?
what is P+Q-R?

Describe in detail how you would construct a 95% confidence interval for a set of 30 data points whose mean is 20 and population standard deviation is 3. be sure to show that you know the formula and how to plug into it. also, clearly state the margin of error.

Suppose i flip two identical coins. what is the probability that i get one head and one tail?

Tod does not have any cookies. david gives jeff 8 cookies. then he splits half of the cookies he has left with tod. david let’s c represent the number of cookies that he starts with. he finds the number of cookies that tod has is 1/2 the difference of c and 8. write an expression to represent the number of cookies that tod has.