What is the value of the expression below when z = 2?

5z^2 - z - 4

An an average person has 6×10 by the power of two as many red blood cells as white blood cells a small sample of the blood has 7×10 by the power of three white blood cells about how many red blood cells are in the sample

Add the fractions, and simply the result to lowest terms. 2/3 + 2/7= ?

The holiday party will cost $160 if 8 people attend. if there are 40 people who attend the party, how much will the holiday party cost