Question

помогите пожалуйста​

Answer 1

Ответ:

$\left \{ {{xy-x=4} \atop {y=7-2x}} \right. \\x*(7-2x)-x=4\\ x=1\ x=2\\y=7-2*1\\y=7-2*2\\y=5\ y=3\\(x_{1},y_{1} )=(1,5)\\(x_{2} ,y_{2} )=(2,3)\\\\\left \{ {{1*5-1=4} \atop {2*1+5=7}} \right. \\\left \{ {{2*3-2=4} \atop {2*2+3=7}} \right. \\\left \{ {{4=4} \atop {7=7}} \right. \\\left \{ {{4=4} \atop {7=7}} \right. \\(x_{1} ,y_{1} )=(1,5)\\(x_{2} , y_{2} )=(2,3)$

Объяснение:

Answer 2

Ответ:

x = 2      y = 3

x = 1       y = 5

Объяснение:

{ xy-x = 4

{ 2x+y = 7

{ xy-x = 4

{y = 7-2x

7x-2x²-x = 4

2x²-6x+4 = 0

D = b²-4ac = 36-32 = 4

x₁ = (-b+√D)/2a = (6+2)/4 = 2

x₂ = (-b-√D)/2a = (6-2)/4 = 1

тогда:

y₁ = 7-2x₁ = 7-4 = 3

y₂ = 7-2x₂ = 7-2 = 5