Prove by induction that: is divisible by 6, for n>0

For n =1,

1(1^2 + 3x1 + 2) = 6

true for n =1

assume true for n = k

For n = k + 1,

should be divisible by 6

LHS =

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=

=

=

=

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=

now I'm stuck. That is obviously not divisible by 6 because M + 3/k is not an integer

HELP

Thank you in advance