The function f(x) varies directly with x and f(x)= 90 when x=30. What is f(x) when x=6?

1 Answer
Jun 21, 2018

#f(x)=18#

Explanation:

#"the statement is "f(x)propx#

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

#f(x)=kx#

#"to find k use the given condition"#

#f(x)=90" when "x=30#

#f(x)=kxrArrk=(f(x))/x=90/30=3#

#"equation is " color(red)(bar(ul(|color(white)(2/2)color(black)(f(x)=3x)color(white)(2/2)|)))#

#"when "x=6" then"#

#f(x)=3xx6=18#