$\"\"$

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Observe the graph :

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The line passing through the points $\"\"$ and $\"\"$ .

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Find the constant of variation of the equation:

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The statement $\"\"$ varies directly as $\"\"$ , means that when $\"\"$ increases, $\"\"$ increases by the same factor.

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Hence $\"\"$ and $\"\"$ always have the same ratio.

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The constant of variation of the equation and the slope of the line have the same value.

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$\"\"$ (Direct variation formula)

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Consider the point is $\"\"$ .

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$\"\"$ (Substitute $\"\"$ )

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$\"\"$ (Simplify)

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Therefore, the constant of direct variation of the equation is $\"\"$ .

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$\"\"$

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Find the slope :

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$\"\"$ .

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$\"\"$ (Formula for slope)

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$\"\"$ (Substitute $\"\"$ and $\"\"$ )

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$\"\"$ (Simplify)

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$\"\"$ (Simplify)

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Therefore, the slope is $\"\"$ .

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$\"\"$

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The constant of variation is $\"\"$ .

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The slope is $\"\"$ .