Объяснение:
zad.2.
1)
4/12xy- 11/18xy= (3*4-2*11) / 36xy=(12-22)/36xy=-10/36xy=-5/18xy
2)
(3a-4b)/a + (8a²+4b²)/ab= [b(3a-4b)+8a²+4b²]/ab=
= (3ab-4b²+8a²+4b²)/ab= (3ab+8a²)ab=a(3b+8a)/ab=
=(8a+3b)/b
3)
5-(4m+5n)/n=[5n-(4m+5n)]/n=(5n-4m-5n)/n=-4m/n
4)
(a²+b²)/2a-b) +2a+b)= [a²+b²+(2a-b)(2a+b)]/(2a-b)=
=(a²+b²+4a²-b²)/(2a-b)=5a²/(2a-b)
