How do you find the positive and negative intervals of a function

Identify the parent function that can be used to graph the function f(x)= (1/4x)^3

An objects motion is described by the equation d= 4sin (pi t) what will the height of the object be at 1.75 seconds?

Afruit stand has to decide what to charge for their produce. they need $10 for 4 apples and 4 oranges. they also need $15 for 6 apples and 6 oranges. we put this information into a system of linear equations. can we find a unique price for an apple and an orange?