1237-(235-(10x+9x+23))=809 решить дам 30 баллов!!!!!!
1237-(235-(10х+9х+23))=809 1237-(235-10х-9х-23)=809 1237-235+10х+9х+23=809 10х+9х=809-1237+235-23 18х= -216 Х= - 216:18 Х= - 12