а) 500-400/(х+43)=495
400/(х+43)=500-495
400/(х+43)=5
х+43=400:5
х+43=80
х=80-43
х=37
б)(270/ y-12)*70=1260
270/у-12=1260:70
270/у-12=18
270/у=18+12
270/у=30
у=270:30
у=9
a)-400/(x+43)=-5
-5(x+43)=-400
-5x=-185
x=37
b) 270/y-12=18
270/y=30
y=9
