y varies jointly with the cube of x and the square of z and inversely with the square of the sum of x and z if y = 72 when x= 2 and z=3 , then find the value of y when x= -1 and z=5.....thx...... I am very lost plz explain all work and answers in detail thx
2007-01-29 15:15:08 · 4 answers · asked by Anthony V 1 in Education & Reference ➔ Homework Help
Does jointly mean directly? If so, the equation would be
y = k (x^3 z^2) over (x+z)^2 where k is the constant of variation
Plugging in 72 for y, 2 for x and 3 for z gives 72 = 2.88k, so k = 25
Now just put that in for k and put -1 for x and 5 for z
2007-01-29 15:21:35 · answer #1 · answered by hayharbr 7 · 2⤊ 0⤋
Jointly just means that some parts of it are in direct variation and some are indirect. Other than that, hayharbr (or whatever his name is) has it right.
2007-01-29 15:31:28 · answer #2 · answered by Anonymous · 0⤊ 0⤋
mr pea tear grif fin says poke a boy for math answers.
2007-01-29 15:19:08 · answer #3 · answered by ihateacaf0 3 · 0⤊ 2⤋
i dont know
2007-01-29 15:17:40 · answer #4 · answered by michaelluciano0401 1 · 0⤊ 1⤋