Объяснение:

1. 9ab/(8ab-6a²)= 9b/(8b-6a)

a=1;b=2

9×2/(8×2-6×1)=18/(16-6)=18/10=1,8

2. 2x / (x²-64) - 1/(x-8)=2x/(x-8)(x+8) - 1/(x-8)=(2x-x-8)/(x-8)(x+8)=(x-8)/(x-8)(x+8) = 1/(x+8)

x= -4

1/(-4+8) = 1/4 = 0,25

3. a/(5a-1) ÷ a²/(25a²-10a+1)=a/(5a-1) × (5a-1)²/a²=(5a-1)/a

a=1/6

(5×1/6 - 1)/1/6 =(5/6-1)÷1/6 = -1/6×6/1=-1