The expression is .
Square of sum: .
(Substitute
)
(Evaluate powers:
)
(Evaluate powers:
)
(Multiply:
)
(Multiply:
)
Horizontal method:
\Rewrite as the sum of three products.
\Apply distributive property: .
\
(Powers of product property:
)
\
(Multiply:
)
Apply distributive property: .
\
(Multiply:
)
(Powers of product property:
)
Apply distributive property: .
(Multiply:
)
\
(Multiply:
)
(Group like terms)
(Add:
)
(Subtract:
)
The product of .
The product of .