[tex]y- wiek\ mamy\\x -wiek\ corki\\\\\left \{ {{y=7x} \atop {(y+10)+(x+10)=60}} \right. \\\\\left \{ {{y=7x} \atop {(7x+10)+(x+10)=60}} \right. \\\\\left \{ {{y=7x} \atop {7x+10+x+10=60}} \right. \\\\\left \{ {{y=7x} \atop {8x+20=60}} \right. \\\\\left \{ {{y=7x} \atop {8x=40}} \right. \\\\\left \{ {{y=7x} \atop {x=5}} \right. \\\\\left \{ {{y=7\cdot5} \atop {x=5}} \right. \\\\\left \{ {{y=35} \atop {x=5}} \right.[/tex]
