Question

If y varies directly as x, and if x is divided by 9, then the y value will be?
a. multiplied by 9 
b. remains the same
c. divided by 9
d. none of these

Answer 1

$\bf \qquad \qquad \textit{direct proportional variation} \\\\ \textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby \begin{array}{llll} k=constant\ of\\ \qquad variation \end{array}\\\\ -------------------------------\\\\ \boxed{x=\cfrac{x}{9}}\qquad y=k\cfrac{x}{9}\implies y=\cfrac{kx}{9}\implies 9y=kx$