Ok its an easy one... heres ur answer....
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= limit (x tending to -3) of { [x^2 - 9] / [root(x^2 + 16) - 5] }
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Multiplying and dividing by[root(x^2 + 16) + 5] to rationalise the denominator:-
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=limit (x tending to -3) of {[x^2 - 9] *[root(x^2 + 16) + 5]/ [root(x^2 + 16) - 5] *[root(x^2 + 16) + 5]}
=limit (x tending to -3) of { [x^2 - 9] *[root(x^2 + 16) + 5]/ [x^2 + 16 - 52] }
=limit (x tending to -3) of { [x^2 - 9] *[root(x^2 + 16) + 5]/ [x^2 + 16 - 25] }
= limit(x tending to -3) of { [x^2 - 9] *[root(x^2 + 16) + 5]/ [x^2 - 9] }
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Here we can cancel out[x^2 - 9] in denominator and numerator.
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=limit(x tending to -3) of { [x^2 - 9] *[root(x^2 + 16) + 5]/ [x^2 - 9] }
= limit(x tending to -3) of [root(x^2 + 16) + 5]
= [root(9+16) + 5]
= root(25) + 5
= 5 + 5
= 10
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