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

question 58

Multiple Choice

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

• A) \(\cos ^ { 2 } 7 x - \sin ^ { 2 } y\)
• B) \(\cos ^ { 2 } 7 x + \sin ^ { 2 } 4 y\)
• C) \(\cos ^ { 2 } 7 x - \sin ^ { 2 } 4 y\)
• D) \(\cos ^ { 2 } x - \sin ^ { 2 } 4 y\)
• E) \(\cos ^ { 2 } x - \sin ^ { 2 } y\)

---

Definitions:

Intrusive Thoughts

Unwanted thoughts or images that repeatedly enter a person's mind, causing distress or discomfort.

Personality Disorders

Mental disorders characterized by enduring maladaptive patterns of behavior, cognition, and inner experience.

Borderline

Refers to Borderline Personality Disorder (BPD), a mental health condition characterized by unstable moods, behavior, and relationships.

Neurosis

A nineteenth-century term for anxiety disorders and several other psychological problems (plural neuroses). Still in popular usage.