10*х=8*25 х: 20=4800: 80 (х-380)*50=2000 (х+8): 70=4 640: (25-х)=40 2700: (х-12)=90

10*х=8*25
х＝8*25
х＝200
х＝200/10
х＝20

х/20＝4800/80
х＝60
х＝60*20
х＝1200

（х-380）*50＝2000
х＝2000/50
х＝40
х＝380+40
х＝420