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| 1. |
Show that the no 7n cannot end with digit 0 |
| Answer» If 7ⁿ ends with a 0 the it must be divisible by 10 i.e., its prime factors should have the factors of both 2 and 5 since 2×5=10.But, 7ⁿ=(7×1)ⁿTherefore by the fundamental theorem of arithmetic (there is no prime factors of 7 other than 7 and 1) we can conclude that 7ⁿ can not end with zero. | |