Question

.

Answer 1

\[\sum_{k=1}^{4}(k-1)(k-2)\]

Answer 2

Use Distributive Law to Remove the Bracket

Answer 3

\[k^2-2k-k+2 = k^2-3k+2\]

\[\sum_{k=1}^{4} k^2-3k+2\]

Answer 4

ok

Answer 5

so that is the expanded form?

Answer 6

because the sum has to equal to 8..