Simplify the Expression Algebraically $\cos ( 7 x + 4 y ) \cos ( 7 x - 4 y )$

question 73

Multiple Choice

Simplify the expression algebraically.
$\cos ( 7 x + 4 y ) \cos ( 7 x - 4 y )$

---

Definitions:

Fort Ticonderoga

A historic fort in New York that played a strategic role in the American Revolutionary War after being captured by American forces in 1775.

Lake Champlain

A natural freshwater lake in North America, mainly within the borders of the United States (Vermont and New York) but partially situated in Canada, known for its recreational value and historical significance.

Boston Massacre

A confrontation on March 5, 1770, in which British soldiers killed five colonial civilians in Boston, escalating tensions leading to the American Revolution.

Manslaughter

A legal term for the killing of a human being without the intention to do so, either in a voluntary act in the heat of the moment or involuntarily through negligence.