Aquantity x varies directly with y and inversely with z. which expression represents the constant of variation, k?
a) xz/y
b) xy/z
c) z/xy
d) y/xz

Pls brainliest will be awarded if answer is correct

What is a correct first step in solving the inequality-4(3-5x)> -6x+9

The length of a rectangular board is 3 feet less than twice its width. a second rectangular board is such that each of its dimensions is the reciprocal of the corresponding dimensions of the first rectangular board. if the perimeter of the second board is one-fifth the perimeter of the first, what is the perimeter of the first rectangular board?