Question

система уравнений 4х-2у=-9 и 3х-3у=-6

Answer 1

Решение:

$left { {{4x-2y=-9} atop {3x-3y=-6}} right\ left { {{4x-2y=-9} atop {2x-2y=-4}} right.\ 2x=-5;\ x=-frac{5}{2}.\ y=frac{4x+9}{2}=frac{4cdot (-frac{5}{2})+9}{2}=-frac{1}{2}. \\ Answer: x=-frac{5}{2}; y=-frac{1}{2}.$

Answer 2

$left { {{4x-2y=-9} atop {3x-3y=-6}} right. left { {{2(2x-y)=-9} atop {3(x-y)=-6}} right. left { {{2x-y=-4.5} atop {x-y=-2}} right. left { {{2(y-2)-y=-4.5} atop {x=y-2}} right.$
2(y-2)-y=-4.5
2y-4-y=-4.5
y=-4.5+4
y=-0.5 или -1/2
х=-0,5-2=-2,5 или -2целых(1/2)
ответ:х=-2,5; у=-0,5