What polynomial identity should be used to prove that 21=25-4?. A. Difference of cubes B. Difference of Squares C. Square of Binomial D. Sum of Cubes

Respuesta :

21 = 25 - 4
21 = 5² - 2²
21 = ( 5 - 2 ) · ( 5 + 2 )
21 = 3 · 7
21 = 21
Answer: B ) Difference of Squares