Which of these functions is not a linear function? Why? f(x)=x-x
f(x)=3x
f(x)=x3
f(x)=23x-2
how am i supposed to know-

What is the 12th term of b(n)=-4-2(n-1)

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?

From the beginning of the day the temperature rose 15 degrees so that by 4 pm it was 87 degrees. what was the temperature at the start of the day