Pls enter fast and pls no fake answers michael decided to put some money in the stock market. he checks at the end of each day to see if the value of the stock has increased or decreased. the table shows the change in his stock value, in dollars, for the first 3 days.

Jeffery conducted a survey in his school and found that 30 of the 50 eighth grade students' favorite subject is mathematics. based on the results, jeffery concluded that out of the 200 students in his school, 120 students' favorite subject is mathematics. select the statement that is true about jeffery's conclusion. a. jeffery's conclusion is not valid because the sample was biased since only 200 students were surveyed. b. jeffery's conclusion is valid because the sample was random since all of the students were eighth grade students. c. jeffery's conclusion is valid because the sample was random. d. jeffery's conclusion is not valid because the sample was biased since all of the students were eighth grade students.

Solve the system of equations. y= 2x y= x^2 - 15

What is the number 321,000,000 in scientific notation? also what is the number? ?