Question

Rozwiąż układ równań:

5 (2x + 3) - 2(3y-4) = 3

3x+ 2 / 4 - y-3/2 = 5

ma wyjść x= -56 y= - 90

a także rozwiąż równanie:

x2 + 3x -y2 - 3y = 6

Answer 1

1)

5 (2x + 3) - 2(3y-4) = 3

 

3x+2     y-3

------ -  -----  = 5 / *4

4          2

 

10x +15 - 6y +8 = 3

3x+2 - 2y +6 = 20

 

10x - 6y = 3-8-15

3x-2y = 20 -2-6

 

10x - 6y = -20

3x-2y = 12/ * (-3)

 

10x - 6y = -20

-9x + 6y = -36

 

x= -56

 

3x-2y =12

3* (-56) - 2y =12

-168 - 2y = 12

-2y = 180 / : (-2)

y= -90

x -56

 

2)

^ - kwadrat

 

x^ + 3x - y^ - 3y = x^ + xy - yx - y^

4x + 3y = 2

 

x^ + 3x - y^ - 3y - x^ + y6 = 0

4x + 3y = 2

 

3x - 3y = 0

4x + 3y = 2

 

7x = 2/ : 7

x= 2/7

 

4x+3y = 2

4 * 2/7 + 3y = 2

3y = 2 - 8/7

3y = 6/7 / :3

y= 2/7

x = 2/7