PLZ HELP Determine if the sequence is arithmetic or geometric, and find the common difference or ratio.

x 1 2 3 4
f(x) 81 72 63 54
Arithmetic, common difference = 9
Arithmetic, common difference = −9
Geometric, common ratio = 9
Geometric, common ratio = −9

Find the average rate of change for f(x) = x2 − 3x − 10 from x = −5 to x = 10.

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.

The base of a triangle exceeds the height by 9 inches. if the area is 180 square inches, find the length of the base and the height of the triangle.