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The curve is $\"\"$ .

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Apply derivative on each side with respect to $\"\"$ .

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$\"\"$

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$\"\"$ .

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Again apply derivative on each side with respect to $\"\"$ .

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$\"\"$

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$\"\"$ .

\

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Find the inflection points.

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Equate $\"\"$ to zero.

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$\"\"$

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$\"\"$ and $\"\"$

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Solve for $\"\"$ .

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The general formula for finding the roots of a quadratic equation is $\"\"$ .

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$\"\"$

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The inflection points at $\"\"$ and $\"\"$ .

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Substitute $\"\"$ in the function.

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$\"\"$

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Substitute $\"\"$ in the function.

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$\"\"$

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Substitute $\"\"$ in the function.

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$\"\"$

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Therefore the inflection points are $\"\"$ , $\"\"$ and $\"\"$ .

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Consider the two points are $\"\"$ and $\"\"$ .

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Find the slope between the two points.

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$\"\"$

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Now consider the two points are $\"\"$ and $\"\"$ .

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Find the slope between the two points.

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$\"\"$

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Observe the two slopes, the slopes are equal.

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Therefore the inflection points are lie in a same straight line.

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The inflection points are lie in a same straight line.