Question

The values of x and y vary directly and one pair of values are given. Write an equation that relates x and y. Simplify completely. x = 0.1, y = 0.9. so y = [?]x i need what is in the brackets and the x. please help me

Answer 1

$\bf \qquad \qquad \textit{direct proportional variation} \\\\ \textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby \begin{array}{llll} k=constant\ of\\ \qquad variation \end{array} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \textit{we also know that } \begin{cases} x=0.1\\ y=0.9 \end{cases}\implies 0.9=k(0.1)\implies \cfrac{0.9}{0.1}=k\implies 9=k \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill y=9x~\hfill$