Question

1 [3x+6y= -48
2x-5y=22


2[x+3y= -16
3x+5y= -20

3[9x+2y= -32
x-3y=9

4[2x-3y= -19
5x+7y=25

Answer 1

OI....

1)

3x + 6y = - 48

2x - 5y = 22

2x = 5y + 22

x = 5y/2 + 11

3.(5y/2+11) + 6y = -48

27y/2 = -81

27y = -162

y = - 162/27  

y = - 6  

x = 5y/2+11

x = (5/2)(-6)+11  

x = - 4  

S = {-6; - 4}

2)

x + 3y = -16

3x + 5y = -20

x = -3y - 16

3.(-3y-16) + 5y = -20

- 4y = 28 ( - 1)

4y = - 28  

y = - 28/4

y = - 7  

x = -3y-16

x = -3(-7)-16  

x = 5  

S = {-7; 5}

3)

9x + 2y = -32

x - 3y = 9      

x = 3y + 9

9.(3y+9) + 2y = -32

29y = -113

29y = - 113  

y = - 113/29

 

x = 3y+9

x = 3(-113/29)+9  

x = -78/29  

S = { - 113/29; - 78/29 }

4)

2x - 3y = -19

5x + 7y = 25

7y = -5x + 25

y = - 5x/7 + 25/7

2x - 3.(-5x/7+25/7) = -19

29x/7 = -58/7

29x = -58

x = - 58/29  

x = -2

y = -5x/7+25/7

y = -(5/7)(-2)+25/7  

y = 5  

S = {-2; 5}

Espero ter ajudado.