Question

РЕШИТЕ ПЖ ПО БЫСТРОМУ а я вам 50 балов ​

Answer 1

1)$\left \{ {{x-5y=8} \atop {2x+4y=30}} \right.$                    

$\left \{ {{x=8+5y} \atop {2x+4y=30\\}} \right.$

$\left \{ {{x=8+5y} \atop {2(8+5y)+4y=30}} \right.$

$\left \{ {{x=8+5y} \atop {16+10y+4y=30}} \right.$

$\left \{ {{x=8+5y} \atop {16+14y=30}} \right.$

$\left \{ {{x=8+5y} \atop {14y=30-16}} \right.$

$\left \{ {{x=8+5y} \atop {14y=14}} \right.$

$\left \{ {{x=8+5y} \atop {y=1}} \right.$

$\left \{ {{x=8+5*1} \atop {y=1}} \right.$

$\left \{ {{x=13} \atop {y=1}} \right.$

Ответ: (X,Y)=(13,1)

2) $\left \{ {{2x-y=1} \atop {7x-6y=-4}} \right.$

$\left \{ {{y=-1+2x} \atop {7x-6y=-4}} \right.$

$\left \{ {{y=-1+2x} \atop {7x-6(-1+2x)=-4}} \right.$

$\left \{ {{y=-1+2x} \atop {7x+6-12x=-4}} \right.$

$\left \{ {{y=-1+2x} \atop {-5x+6=-4}} \right.$

$\left \{ {{y=-1+2x} \atop {-5x=-4-6}} \right.$

$\left \{ {{y=-1+2x} \atop {-5x=-10}} \right.$

$\left \{ {{y=-1+2x} \atop {x=-10:-5}} \right.$

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

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

$\left \{ {{y=3} \atop {x=2}} \right.$

ОТВЕТ: (X,Y)=(2,3)