Answer:
The star * can be replaced by <em>2bc</em>
Step-by-step explanation:
<u>Square Of A Binomial
</u>
The expression
can be expanded as
. Equivalently, if we have the expansion we can reduce to the power of 2. If we know a term is the square of a monomial, we can find the original term by taking the square root.
The given expression is

It's supposed to be the square of a binomial, so we need to test if both of the given terms are perfect squares


Once we are sure we have both square terms, we can complete the expression with the remaining part of the expansion, i.e. twice the first by the second term. In other words

The full expression will be

which can be reduced to
