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Question
If a + b = 6 and ab = 20, find the value of a3 − b3
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Solution
In the given problem, we have to find the value of `a^3 - b^3`
Given `a-b = ,ab = 20`
We shall use the identity
`a^3 -b^3 = (a-b)^3 3ab (a-b)`
`a^3 -b^3 = (a-b)^3 + 3ab(a-b)`
`a^3 - b^3 = (6)^3 3 xx 20(6)`
`a^3 - b^3 = 216 +360`
`a^3 -b^3 = 576`
Hence the value of `a^3 - b^3`is 576.
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