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1. Prove by induction that for all integers n1,

4+8+12+...+4n = 2n^2+2n

2. A number a is divisible by b if the remainder of dividing a by b is zero. For example 10 is divisible by 5 but 11 is not divisible by 5.

Prove by induction that for all integers n1,11^n - 6 is divisible by 5.

3. Prove by induction that for all integers n 1, 3^n 2^n+n^2