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Evaluate the following limits: limx→5[x3-125x2-25] - Mathematics and Statistics

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Question

Evaluate the following limits: `lim_(x -> 5)[(x^3 - 125)/(x^2 - 25)]`

Sum
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Solution

`lim_(x -> 5)(x^3 - 125)/(x^2 - 25)`

= `lim_(x -> 5) ((x^3 - 125)/(x^2 - 25))/((x^2 - 25)/(x - 5))    ...[("As"  x -> 5","  x ≠ 5),(therefore x - 5 ≠ 0),("Divide Numerator and"),("Denominator by"  x - 5.)]`

= `lim_(x -> 5)(((x^3 - 5^3)/(x - 5)))/(((x^2 - 5^2)/(x - 5))`

= `(3(5)^2)/(2(5)^1)    ...[lim_(x -> "a") (x^"n" - "a"^"n")/(x - "a") = "na"^("n" - 1)]`

= `15/2`

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Chapter 7: Limits - EXERCISE 7.1 [Page 100]

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