14х-9х=125...............15у+25у=120
5х=125.......................40у=120
х=125÷5......................у=120÷40
х=25.............................у=3
__________.............._________
14×25-9×25=125........15×3+25×3=120
125=125........................120=120
13х+5х=108.............29-17у=12×4
18х=108....................-17у=48-29
х=108÷18..................у=19÷(-17)
х=6............................у= -19/17
___________.......____________
13×6+5×6=108.......29-17×(-19/17)=12×4
108=108.........................48=48