Объяснение:
a)
(3x-1)/x² + (x-9)/3x= [3(3x-1)+(x-9)]/ 3x²= (9x-3+x²-9x)/3x²=
= x²-3 /3x²
b)
1/(2a-b) - 1/(2a+b) = (2a+b-(2a-b))/ (4a²-b²) = (2a+b-2a+b)/(4a²-b²)=
= 0/(4a²-b² = 0
c)
5/c+3) - (5c-2)/(c²+3c) = (5c-5c+2)/(c²+3c) = 2/(c²+3c)
