1)
0.75a-b:8 1/11=0.75a-11b/89
при a=11 1/3, b=8.9
0.75*11 1/3 - 11*8 9/10 : 89=3/4*34/3 - (11*89)/10 *1/89=8 2/3-1 1/10=8 20/30-1 3/30=7 27/30=7 9/10=7.9
2)
15 1/6 :x+0.13y
при х=18,2, у=7 1/13
15 1/6 :18 1/5+13/100*7 1/13=91/6*5/91+13/100*92/13=5/6+23/25=125/150+138/150=263/150=1 113/150
3)
n :21 6/23-m/47=23n/489 - m/47
при n=97.8, m=31 1/3, то
23*97 4/5*1/489 - 94/3*1/47=(23*489)/489 - 2/3=23-2/3=22 1/3
4)
c :1 3/7+d:8 15/19=7c/10+19d/167
при с=67 1/7, d=33,4 то
7*470/7+(19*33 1/2)/167=470+(19*67)/2*167=470+1273/334=470+3 271/334=473 271/334