Suppose you have a data set that includes the values 20,30, and 50. If you add a fourth value to this data set and after doing that the mean of the data set is 50
what was the value that you added?
A.-20
8.40
C. 50
D.100
I need help please someone help

The first few steps in solving the quadratic equation 9x2 + 49x = 22 ? 5x by completing the square are shown. 9x2 + 49x = 22 ? 5x 9x2 + 54x = 22 9(x2 + 6x) = 22 which is the best step to do next to solve the equation by completing the square? 9(x2 + 6x + 3) = 25 9(x2 + 6x + 3) = 49 9(x2 + 6x + 9) = 31 9(x2 + 6x + 9) = 103