If [(13!)^16 - (13!)^8] / [(13!)^8 + (13!)^4] = a , what is the unit's digit of a/(13!)^4?
a)0
b)1
c)3
d)5
e)9
OA: e
a)0
b)1
c)3
d)5
e)9
OA: e
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I applied a^2 - b^2 = (a-b)(a+b) for the numeratorgmataug08 wrote:If [(13!)^16 - (13!)^8] / [(13!)^8 + (13!)^4] = a , what is the unit's digit of a/(13!)^4?
a)0
b)1
c)3
d)5
e)9
OA: e
NICE !The units digit of 13! or 13!^4 will always be 0 (since 13! has 10 in it )
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