The diagram shows the line of best fit by plotting \(\dfrac{y}{x}\) against \(x\).

Find the relation between \(y\) and \(x\).

Note that the gradient is \(m=\dfrac{5-1}{6+2}=\dfrac{1}{2}\) which passing through \((6,5)\).

\(\begin{aligned} \dfrac{y}{x}&=mx+c\\ 5&=\dfrac{1}{2}(6)+c\\ 5&=3+c\\ c&=2. \end{aligned}\)

Therefore, the equation is \(\dfrac{y}{x}=\dfrac{1}{2}x+2\) or \(y= \dfrac{1}{2}x^2+2x\).

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