Find the value of the expression 2ab/c when a = -1, b = -4, and c= 2

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.

Acertain volume of water contains 100000 hydrogen atoms and 50,000 oxygen atoms how many hydrogen atoms are in a volume of water containing 4 million oxygen atoms

What is the value of x in the equation7x+2y=48 when y=3