Year 9 simplification maths

your first equivalence:

how is that equivalentl?

 

First (1/3)k = k/3, than it's (k/3)[(k+1)(k+2)] + 1[(k+1)(k+2)]. The rest should be clear, I hope

 

yep got it. been about 15 years since i had an algebra quiz. and as you know alot of us in life don't maintain that skill in our day to day existence.