Question

The unit's digit of 7^51!^31!
is​

Answer 1

Answer:

the unit digit is 0

hope it will help ......

Answer 2

Answer:

1

Step-by-step explanation:

The unit's digit of 7^51!^31!  is 1​

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7^4 unit digit = 1, so number 7^4k = (10n+1)^m will have 1 as its unit digit

• We need to proof that 51!^31! is multiple of 4.

• 51!= 1*2*3*4*....*48*49*50*51= 4p as it has at least one factor of 4
• (4p)^31!= 4s - as any integer power of 4 is multiple of 4

• So the given number 7^51!^31!  can be shown as ...1^m which ends with 1 so unit digit for this number is 1.

Answer: unit digit for given number is 1