Question

решите системы
1)х+2y=11
y+2x=-5
2)у+4х=2
8х+3у=5

Answer 1

1)
$\left \{ {{x+2y=11} \atop {y+x = -5}} \right.$
$\left \{ {{x+2y=11} \atop {y= -5 - 2x}} \right. \left \{ {{x+2(-5-2x)-11=0} \atop {y = -5-2x}} \right. \left \{ {{x -10-4x-11=0} \atop {y= -5 - 2x}} \right. \left \{ {{-3x-21=0} \atop {y= -5 - 2x}} \right. \left \{ {{x=-7} \atop {y=9}} \right.$
2)
$\left \{ {{y+4x=2} \atop {8x+3y=5}} \right.$
$\left \{ {{y=2-4x} \atop {8x+3(2-4x)-5=0}} \right. \left \{ {{y=2-4x} \atop {8x+6-12x-5=0}} \right. \left \{ {{y=2-4x} \atop {1-4x=0}} \right. \left \{ {{y=2-4x} \atop {x= \frac{1}{4} }} \right. \left \{ {{y=2-4* \frac{1}{4} } \atop {x= \frac{1}{4} }} \right. \left \{ {{y=1} \atop {x= \frac{1}{4}}} \right.$