Question 475789
if w is jointly proportional to the cube of x and to the cube root of y, and w=336 when x=2 and y=216, then
:
A.) find a general formula to describe the relationship (use fractional exponents rather than radicals, if necessary)
Let k = constant of the variation
w = {{{x^3*y^(1/3)*k}}}
w=336 when x=2 and y=216,
{{{2^3*216^(1/3)*k}}} = 336
8 * 6 * k = 336
48k = 336
k = {{{336/48}}}
k = 7
the formula
w = {{{7*x^3*y^(1/3)}}}
:
:
 and
B.) use the formula to find w when x=8 and y=8.
w = {{{7*8^3*8^(1/3)}}}
w = 7 * 512 * 2
w = 7168