48:(3 4/5х-25)=1 1/2
1) 3 4/5=(4+3×5)/5=19/5
т.е. 19/5 x
2)1 1/2=(1+1×2)/2=3/2
3)3/2(19/5x-25)=57/10x-75/2=
(3/2×19/5x=57/10x
3/2×(-25/1)=-75/2)
4)48=57/10x-75/2
57/10x=48+75/2
5)48+75/2=48/1+75/2=96/2+75/2=171/2
6)
x=171/2×10/57
x=171/1×5/57
x=855/57
x=15