$\"\"$

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The slope m of a non vertical line through any two points is given by,

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$\"\"$

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Substitute $\"\"$ in rate of change

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formula.

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$\"\"$

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$\"\"$

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$\"\"$ (Subtract: 8 – 4 = 4)

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$\"\"$ (Multiply each side by (x–2))

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$\"\"$ (Cancel common terms)

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$\"\"$

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$\"\"$ (Distributive property: a(b + c) = ab + ac)

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$\"\"$ (Multiply: $\"\"$ )

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$\"\"$ (Add 1 to each side)

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$\"\"$ (Additive inverse property: $\"\"$ )

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$\"\"$ (subtract: 4 - 1 = 3)

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$\"\"$ (Multiply each side by -2)

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$\"\"$ (Cancel common terms)

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$\"\"$ (Multiply: $\"\"$ )

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$\"\"$

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The value of $\"\"$ .