tolong dijawab please

1) (3a/4) + (2a/5)
={ (3a.5) + (2a.4) } / (4 . 5)
= (15a + 8a) / 20
= 23a / 20

2) (7/2a) - (2/3a)
= {(7.3a) - (2.2a)} / (2a.3a)
= (21a - 4a) / 6a²
= 17a / 6a²
= 17 / 6a

3) (2a/9) × (1/4b)
= 2a/36b
= a / 18b

4) (3a²/5b) ÷ (2a/3)
= (3a²/5b) × (3/2a)
= 9a² / 10ab
= 9a / 10b

5) (5a/b)²
= 25a² / b²