Помогите мне 3* х-7800=1200

(у+2958):57=139

38007:(5000-z)=9

3×х-7800=12003×х=7800+12003×х=9000х=9000:3х=3000(у+2958):57=139у+2958=57×139у+2958=7923у=7923-2958у=496538007:(5000-z)=95000-z=38007:95000-z=4223z=5000-4223z=777