If f(x)= \frac{-4}{7\sqrt{x} }[/tex] , what is the value of f(4) , to the nearest ten-thousandth(if necessary)?

Suppose that a households monthly water bill (in dollars) is a linear function of the amount of water the household uses (in hundreds of cubic feet, hcf). when graphed, the function gives a line with slope of 1.65. if the monthly cost for 13 hcf is $46.10 what is the monthly cost for 19 hcf?