Question 17
Algebraic ExpressionsFactorize completely 4a2 − 12ab − c2 + 9b2?
- A.4a(a − 3b) + (3b − c)2
- B.(2a + 3b − c)(2a + 3b + c)
- C.4a(a − 3b) + (3b + c)2
- D.(2a − 3b − c)(2a − 3b + c)
Show the answer and explanation
Answer: D ((2a − 3b − c)(2a − 3b + c))
Explanation
Group 4a² − 12ab + 9b² = (2a − 3b)². Then (2a − 3b)² − c² is a difference of two squares: (2a − 3b − c)(2a − 3b + c).