tentang perkalian dan pembagian aljabar, no 4, 5, 6

4a) 3x(2x² - 5y + 4)
= 6x³ - 15xy + 12x
b) (3k - 4)(1 - 2k)
= 3k - 4 + 6k² + 8k
= 6k² + 11k - 4
c) (5m + 3)(4m² - m + 6)
= 20m³ + 12m² - 5m² - 3m + 30m + 18
= 20m³ + 7m² + 27m + 18
d) (3 - a)(3a + 4)(a - 2)
= (9a - 3a² + 12 - 4a)(a - 2)
= (- 3a² - 13a + 12)(a - 2)
= - 3a³ + 6a² - 13a² + 26a + 12a - 24
= - 3a³ - 7a² + 38a - 24

5) 20xy² ÷ 5xy
= 4y
b) 18a²b²c ÷ (-3ab²)
= (- 6ac)
c) 12p⁴q³r ÷ 2p³q ÷ 3pr
= 6pq²r ÷ 3pr
= 2q²
d) 15m⁴n³ ÷ (12m³n ÷ 4mn)
= 15m⁴n³ ÷ 3m²
= 5m²n³

6) 8x² + 14x - 15
-------------------------
2x + 5
= (2x + 5)(4x - 3)
--------------------------
(2x + 5)
= 4x - 3

b) 2x³ - 5x² + 7x - 10
-------------------------------
x - 2
= (x - 2)(2x² - x + 5)
-----------------------------
x - 2
= 2x² - x + 5