What is -3/4x + 1/2y - 9/4x - 11/2y in simplest form?

Acertain population of bacteria demonstrates exponential growth doubles in size every 4 days. how long will it take the population to triple in size?

Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard deviation 0.070 g. a vending machine will only accept coins weighing between 5.48 g and 5.82 g. what percentage of legal quarters will be rejected? round your answer to two decimal places.

y=2x−1 5x−4y=1 is (1,1)(1,1) a solution of the system?