câu 2 :
3x=6y=>x/6=y/3
áp dụng...ta có:
x/6=y/3=x+y/6+3=45/9=5
=>x/6=5=>x=30
=>y/3=5=>y=15
câu 3:
-6x=5y=>x/5=y/-6=>-4x/-20=5y/-30
áp ..ta có:
-4x/-20=5y/-30=-4x-5y/-20-(-30)=-60/10=-6
=>x/5=-6=>x=-30
=>y/-6=-6=>y=36
câu 4:
2,(703)=2+0,(703)=2+703/999=73/27