10 points and brainliest to correct answer plz

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

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?

X^2/100+y^2/25=1 the y-intercepts are at: a) (-10,0) and (10,0) b) (0,10) and (0,5) c) (0,-5) and (0,5)