Subtract and simplify. (2x^2+5x-+7x-1)

What basic trigonometric identity would you use to verify that sin x cos x tan x =1-cos^(2)x?

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?