Aphrodite1228
Answered

Which does not show a direct variation between x and y?  
A.y = x/9  B.y = 2x  C.y = 0.5x  D.y = 9/x

If f(x) varies directly with x, and f(x) = 8 when x = 6, write the direct linear variation equation. 
 A. f(x) = 3/4x  B.f(x) = 6x  C.f(x) = 8x  D.f(x) = 4/3x

Find the constant of variation for the relationship f(x)= 30x.  A.10  B.30  C.x  D.f(x)


If f(x) varies directly with x, and f(x) = 56 when x = 8, find the value of f(x) when x = 2  A.4  B.7  C.8  D.14



Answer :

kate200468
[tex](1)\\direct\ variation\ between\ x\ and\ y:\ \ \ y=k\cdot x\ \ \ and\ \ \ k\in\ R\\\\Ans.\ NOT\ direct\ is\ D\\\\(2)\\f(x) = m\cdot x\ \ \ and\ \ \ f(6)=8\\\\ \Rightarrow\ \ \ m\cdot 6=8\ \ \ \Rightarrow\ \ \ m= \frac{8}{6} = \frac{4}{3} \ \ \ \ \Rightarrow\ \ \ \ Ans.\ D\\\\(3)\\f(x)=30x\ \ \ \Leftrightarrow\ \ \ \frac{f(x)}{x} =30\ \ \ \ \ \ \Rightarrow\ \ \ \ constans=30\ \ \ \ Ans.\ B.[/tex]

[tex]\\\\(4)\\f(x)=m\cdot x\ \ and\ \ f(8)=56\\\\m\cdot8=56\ \ \Leftrightarrow\ \ m= \frac{56}{8} =7\ \ \Rightarrow\ \ \ f(x)=7x\ \ \ \Rightarrow\ \ \ f(2)=7\cdot2=14\\\\Ans.\ D.[/tex]