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Which of the following numbers is divisible by 310+23^{10} + 2?

Solution

✅ Correct Option: 4

We need to check divisibility by 310+23^{10}+2. Let’s denote

N=310+2N = 3^{10}+2.

Check option 1: 320+43^{20}+4

Write 320+4=(310)2+43^{20}+4 = (3^{10})^2+4.

Since N=310+2N=3^{10}+2, substitute 310=N−23^{10} = N-2.

So 320+4=(N−2)2+4=N2−4N+83^{20}+4 = (N-2)^2+4 = N^2-4N+8.

Clearly divisible by NN? No, because remainder =−4N+8= -4N+8, not multiple of NN.

So not divisible.


Check option 2: 330+23^{30}+2.

330+2=(310)3+2=(N−2)3+23^{30}+2 = (3^{10})^3+2 = (N-2)^3+2.

Expand: (N3−6N2+12N−8)+2=N3−6N2+12N−6(N^3 - 6N^2 + 12N - 8)+2 = N^3 - 6N^2 + 12N - 6.

This is divisible by NN? Yes, because N3N^3, −6N2-6N^2, 12N12N are multiples of NN, remainder −6-6.

So not divisible.


Check option 3: 320+83^{20}+8.

320+8=(310)2+8=(N−2)2+8=N2−4N+123^{20}+8 = (3^{10})^2+8 = (N-2)^2+8 = N^2-4N+12.

Clearly divisible? Terms: N2−4NN^2-4N divisible, remainder 1212.

So not divisible.


Check option 4: 330+83^{30}+8.

330+8=(310)3+8=(N−2)3+8=(N3−6N2+12N−8)+8=N3−6N2+12N3^{30}+8 = (3^{10})^3+8 = (N-2)^3+8 = (N^3-6N^2+12N-8)+8 = N^3-6N^2+12N.

This equals N(N2−6N+12)N(N^2-6N+12), which is divisible by NN.

So divisible.


Answer: 330+8 3^{30}+8

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