Pls do all or 2 and put the day and which one

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

Solve the equation below: (x+4)/6x=1/x a. x=2 b. x=0,2 c. x=-2 d. x=0,-2

In one day there are too high tides into low tides and equally spaced intervals the high tide is observed to be 6 feet above the average sea level after six hours passed a low tide occurs at 6 feet below the average sea level in this task you will model this occurrence using a trigonometric function by using x as a measurement of time assume the first high tide occurs at x=0. a. what are the independent and dependent variables? b. determine these key features of the function that models the tide: 1.amplitude 2.period 3.frequency 4.midline 5.vertical shift 6.phase shift c. create a trigonometric function that models the ocean tide for a period of 12 hours. d.what is the height of the tide after 93 hours?