If y varies inversely as x, and y = 18 when x = 2, how do you find y when x = 4?

2 Answers
May 21, 2018

Answer:

y = 9

Explanation:

If x is doubled then y is cut in half, since they are inversely related

# 18/2 =9#

May 21, 2018

Answer:

#y=9#

Explanation:

#"the initial statement is "yprop1/x#

#"to convert to an equation multiply by k the constant"#
#"of variation"#

#rArry=kxx1/x=k/x#

#"to find k use the given condition"#

#y=18" when "x=2#

#y=k/xrArrk=yx=18xx2=36#

#"equation is " color(red)(bar(ul(|color(white)(2/2)color(black)(y=36/x)color(white)(2/2)|)))#

#"when "x=4" then"#

#y=36/4=9#