1.1) 3х/5 = 9х/15; 1.2) 2аb/3 =2а³b² / 3а²b; 1.3)-mn/2m² = n/-2m.
2.1) 21а²(b-а)/(а²-b²) =-21аα/(а+b).
2.2) 125х²у³/15х³у^4 = 25/3ху.
3.1) (2а+b)/(а²-b²) и 4/(2а+2b) Общий знаменатель а²-b²
4/2а+2b=4/2(а+b)=2/(а+b)=2(а-b)/(а²-b²).
4) (3^8 · 17^7)/51^6=3·51^7/51^6=3·51=153.
5) (х-3у)/(6х²-54у²)=(х-3у)/6(х-3у)(х+3У)=1/6(х+3у)=1/(6·1/4)=2/3.