Question

Please help

Answer 1

by induction

step1: prove it's true for n = 1 by direct substitution
step2: assume its true for n = k where k is some integer
step 3 : evaluate the LHS for n = k+ 1 => this means adding 2(k+1) to LHS
step4: also add 2(k+1) to RHS, because you can -- and *must* to keep the equality -- and see if that makes the RHS same as the formula suggests it should be ie (k+1)^2 + (k+1)
if so you have proved it. if not, you haven't.