kalikanlah 1. 7 x 4a x b 2. 3m x 2m x n 3. 4ab x (-2ab) 4. 5ab x 7ab 5. 2 (4a + 7) 6. 3(2m - 7) 7. 5a(a + 2b) 8. (m + 5) (m + 7) 9. (2n + 3)(n + 2) 10. (2a - 4)

1) 7 × 4a × b
= 28a × b
= 28ab

2) 3m × 2m × n
= 6m² × n
= 6m²n

3) 4ab × (-2ab)
= -8a²b²

4) 5ab × 7ab
= 35a²b²

5) 2 (4a + 7)
= 8a + 14

6) 3 (2m - 7)
= 6m - 21

7) 5a (a + 2b)
= 5a² + 10ab

8) (m + 5) (m + 7)
= m² + 7m + 5m + 35
= m² + 12m + 35

9) (2n + 3) (n + 2)
= 2n² + 4n + 3n + 6
= 2n² + 7n + 6

10) (2a - 4) (3a - 8)
= 6a² - 16a - 12a + 32
= 6a² - 28a + 32