I need help please help

An airplane travels at an unknown elevation before it descends 3 miles to an elevation of 15 miles. find the elevation of the plane before its descen.

Jude is making cement for a driveway. the instructions show the amount of each ingredient to make 1 batch of cement. complete each statement to adjust the ingredients for each new situation if jude uses these instructions.

Which of the following equations is equivalent to x/3-6/x=1