Question #f65fd

1 Answer
Mar 1, 2017

#k=2#

Explanation:

Consider each statement separately.

#• ypropx^2larrcolor(blue)" direct variation"#

#• yprop1/zlarrcolor(blue)" inverse variation"#

Combine the right sides as a product.

#• ypropx^2/zlarrcolor(blue)" joint variation"#

Convert to an equation by introducing k,
#color(blue)" the constant of variation"#

#rArry=kxxx^2/z#

#rArry=(kx^2)/z#

#color(blue)"cross-multiplying" # gives.

#kx^2=yz#

#rArrk=(yz)/x^2#

To calculate k, substitute the given values for x, y and z

#rArrk=(6xx27)/9^2=162/81=2#

#"the equation of variation is "color(red)(bar(ul(|color(white)(2/2)color(black)(y=(2x^2)/z)color(white)(2/2)|)))#