NEED HELP ASAP Which side lengths form a right triangle?

After being rearranged and simplified, which of the following equations could be solved using the quadratic formula? check all that apply. a. 9% + 3x2 = 14 + x-1 b. -x+ + 4x + 7 = -32-9 c. 5x + 4 = 3x4 - 2 d. 2x2 + x2 + x = 30

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

Whats the name of the vertical axis