-1 31/56*1 7/57*(-2 17/58)=87/56*64/57*133/58=(87*8*133)/(7*57*58)=
=(87*8*19)/(1*57*58)=(87*8*1)/(1*3*58)=(3*8*1)/(1*3*2)=4
1 7/58:(-1 21/43)*2 5/41=-(65*43*87)/(58*64*41)=-(65*43*3)/(2*43*41)
x:4=-(65*43*3)/(2*43*41)
x=-(65*43*3)/(2*43*41) *4
x=-(65*43*3)/(32*41)
x=-8385/1312
x=-6 513/1312