Solve each system of equations by substitution y = 2x + 3
y = -x - 9

What is the product of x and y ?

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

Which of the following is the true for f(x) = 5cos

2x minus y equals 6, x plus y equals negative 3