Devon has 14 steel balls of equal weight. if he puts 8 of them in one pan of a balance, and the rest along with a weight of 20 grams in the other pan, the pans balance each other.

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.

How many kilometers are equal to 5 miles? use 1 mile ≈ 1.61 kilometers. !

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?