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76n- 66n, where n is an integer >0, is divisible by
Answer & Solution
Correct Answer:
Option
D
$$\eqalign{
& {7^{6n}} - {6^{6n}} \cr
& = {7^6} - {6^6} \cr
& = {\left( {{7^3}} \right)^2} - {\left( {{6^3}} \right)^2} \cr
& = \left( {{7^3} - {6^3}} \right)\left( {{7^3} + {6^3}} \right) \cr
& = \left( {343 - 216} \right) \times \left( {343 + 216} \right) \cr
& = 127 \times 559 \cr
& = 127 \times 13 \times 43 \cr} $$
Clearly, it is divisible by 127, 13 as well as 559
Clearly, it is divisible by 127, 13 as well as 559
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