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Find an equation passes through the points $\"\"$ , $\"\"$ , $\"\"$ and $\"\"$ .

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Let a cubic function passes through $\"\"$ , $\"\"$ , $\"\"$ and $\"\"$ :

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General form of cubic function $\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$

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$\"\"$ equation $\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$

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$\"\"$ equation $\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$

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$\"\"$ equation $\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$

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$\"\"$ equation $\"\"$ .

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From equation (2), substitute $\"\"$ in other three equations.

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$\"\"$ equation $\"\"$

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$\"\"$ equation $\"\"$

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$\"\"$ equation $\"\"$

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Solution of the above system is $\"\"$ .

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Substitute $\"\"$ and $\"\"$ in $\"\"$ .

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$\"\"$ .

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Graph of $\"\"$ :

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.

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There is no possibility for a straight line graph passes through the points $\"\"$ , $\"\"$ , $\"\"$ and $\"\"$ .

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There are many curves exist passes through $\"\"$ , $\"\"$ , $\"\"$ and $\"\"$ like polynomial functions with various degrees.

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The graph contains the points $\"\"$ , $\"\"$ , $\"\"$ and $\"\"$ :

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.