6 empty cans weigh 3.5 oz. How many cans equal 200 pounds?

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)

The following division is being performed using multiplication by the reciprocal find the missing numbers is 5/12 divided by x/3 equals 5/12 times x/10 equals 1/x

Which shows one way to determine the factors of 4x3 + x2 – 8x – 2 by grouping?