If(x)=-2x-3, find f(-1)

Compare the subtraction problems 6/8 - 5/8 = 1/8 and 6/9 - 7/9 = 1/9 why is the answer to the first problem positive and the answer to the second problem negative

In the xy-plane, if the parabola with equation passes through the point (-1, -1), which of the following must be true?

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