Question

пожалуйста срочно нужна​

Answer 1

( а )

$\left \{ {{x+y=6} \atop {x-y=2}} \right.\\\\\left \{ {{x=6-y} \atop {6-y-y=2}} \right.\\\\\left \{ {{x=6-y} \atop {6-2y=2}} \right.\\\\\left \{ {{x=6-y} \atop {-2y=2-6}} \right.\\\\\left \{ {{x=6-y} \atop {-2y=-4}} \right.\\\\\left \{ {{x=6-y} \atop {y=-4:(-2)}} \right. \\\\\left \{ {{x=6-y} \atop {y=2}} \right.\\\\\left \{ {{x=6-2} \atop {y=2}} \right. \\\\\left \{ {{x=4} \atop {y=2}} \right.$

Проверка:

$\left \{ {{x+y=6} \atop {x-y=2}} \right. \\\\\left \{ {{x=4} \atop {y=2}} \right.\\\\\left \{ {{4+2=6} \atop {4-2=2}} \right. \\\\\left \{ {{6=6} \atop {2=2}} \right.$

( б )

$\left \{ {{x+y=7} \atop {x-y=3}} \right. \\\\\left \{ {{x=7-y} \atop {7-y-y=3}} \right.\\\\\left \{ {{x=7-y} \atop {7-2y=3}} \right.\\\\\left \{ {{x=7-y} \atop {-2y=3-7}} \right.\\\\\left \{ {{x=7-y} \atop {-2y=-4}} \right.\\\\\left \{ {{x=7-y} \atop {y=-4:(-2)}} \right.\\\\\left \{ {{x=7-y} \atop {y=2}} \right.\\\\\left \{ {{x=7-2} \atop {y=2}} \right.\\\\\left \{ {{x=5} \atop {y=2}} \right.$

Проверка:

$\left \{ {{x+y=7} \atop {x-y=3}} \right.\\\\\left \{ {{x=5} \atop {y=2}} \right. \\\\\left \{ {{5+2=7} \atop {5-2=3}} \right. \\\\\left \{ {{7=7} \atop {3=3}} \right.$

( в )

$\left \{ {{x-y=-2} \atop {x+3y=-10}} \right. \\\\\left \{ {{x=-2+y} \atop {-2+y+3y=-10}} \right.\\\\\left \{ {{x=-2+y} \atop {-2+4y=-10}} \right.\\\\\left \{ {{x=-2+y} \atop {4y=-10+2}} \right.\\\\\left \{ {{x=-2+y} \atop {4y=-8}} \right.\\\\\left \{ {{x=-2+y} \atop {y=-8:4}} \right.\\\\\left \{ {{x=-2+y} \atop {y=-2}} \right.\\\\\left \{ {{x=-2-2} \atop {y=-2}} \right.\\\\\left \{ {{x=-4} \atop {y=-2}} \right.$

Проверка:

$\left \{ {{x-y=-2} \atop {x+3y=-10}} \right. \\\\\left \{ {{x=-4} \atop {y=-2}} \right. \\\\\left \{ {{-4-(-2)=-2} \atop {-4+3*(-2)=-10}} \right. \\\\\left \{ {{-4+2=-2} \atop {-4-6=-10}} \right. \\\\\left \{ {{-2=-2} \atop {-10=-10}} \right.$

( г )

$\left \{ {{2x+y=4} \atop {3x-y=1}} \right. \\\\\left \{ {{y=4-2x} \atop {3x-(4-2x)=1}} \right.\\\\\left \{ {{y=4-2x} \atop {3x-4+2x=1}} \right.\\\\\left \{ {{y=4-2x} \atop {3x+2x=1+4}} \right.\\\\\left \{ {{y=4-2x} \atop {5x=5}} \right.\\\\\left \{ {{y=4-2x} \atop {x=5:5}} \right.\\\\\left \{ {{y=4-2x} \atop {x=1}} \right.\\\\\left \{ {{y=4-2*1} \atop {x=1}} \right.\\\\\left \{ {{y=4-2} \atop {x=1}} \right.\\\\\left \{ {{y=2} \atop {x=1}} \right.$

Проверка:

$\left \{ {{2x+y=4} \atop {3x-y=1}} \right. \\\\\left \{ {{y=2} \atop {x=1}} \right. \\\\\left \{ {{2*1+2=4} \atop {3*1-2=1}} \right. \\\\\left \{ {{2+2=4} \atop {3-2=1}} \right. \\\\\left \{ {{4=4} \atop {1=1}} \right.$