Question

The graph of a proportional relationship passes through (3, 24) and (1, y). Find y.

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}\\\\ -------------------------------`


`\bf (\stackrel{x}{3},\stackrel{y}{24})\textit{ we also know that } \begin{cases} x=3\\ y=24 \end{cases}\implies 24=k3\implies \cfrac{24}{3}=k \\\\\\ 8=k\qquad therefore\qquad \boxed{y=8x} \\\\\\ (\stackrel{x}{1},\stackrel{y}{y})\textit{ when x = 1, what is \underline{y}?}\qquad y=8(1)`