X+y=105 и x:y=6 Решите пожалуйста эту систему

[latex] left { {{x=105-y} atop {(105-y):y=6}} ight. extless = extgreater left { {{x=105-y} atop {(105-y)=6*y}} ight. extless = extgreater left { {{x=105-y} atop {6y+y=105}} ight. extless = extgreater left { {{x=105-y} atop {7y=105}} ight. \ extless = extgreater left { {{x=105-y} atop {y=15}} ight. extless = extgreater left { {{x=90} atop {y=15}} ight. [/latex]