Nomer 5 sama 6 +caranya

5.
(7 a^3 b^4) . (3 a^5 b^2)
= 21 a^(3 + 5) b^(4 + 2)
= 21 a^8 b^6

Jawaban : B

6.
(x² + y²) (x² - y²)
= x^(2 + 2) - x²y² + x²y² - y^(2 + 2)
= x^4 - y^4

Jawaban : C