The tub started with how many gallons of water f(x)=-3x=15

What is the y-intercept of the line given by the equation

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $36.98. find the probability that a randomly selected bill will have an amount greater than $173, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

Anewly planted tree needs to b stacked witg three wires.each wire is attached to the trunk 3ft abouve the ground and anchored to the ground 4ft fromthe base of the three