38015

Q1)None of the values of n will 2^n be a multiple of 10 because 2^n will never be a prime factor of 5. 2^1=2, 2^4=16, 2^6=64.

Q2)2^3+3^5=251
2^7+3^9=19811
2^23+3^5=8388851 These are all odd numbers

Q4) any value of n will cause 1^n + 2^n + 3^n to result to an even number, this is because 1^n is always 1, whilst 2^n is an even number and 3^n is always an odd number. Therefore, you are adding an odd and an even number which always gives an odd number and then you are adding 1, which gives an even number; as an odd number and a odd number always add to give an even number.