Question

(1p) 3 Rezolvaţi sistemul: 3x + 2(y +1)=7 2(x-5)+ 3y =-10​

Answer 1

Răspuns:

3x + 2(y +1)=7

2(x-5)+ 3y =-10​

_____________

3x+2y+2=7

2x-10+3y= -10

_________

3x+2y=7-2

2x+3y=-10+10

_________

3x+2y=5 I ×2

2x+3y=0 I × (-3)

_____________

6x+4y=10

-6x-9y=0

________

 /  -5y=10=>y=-10:5=>y=-2

3x+2·(-2)=5

3x-4=5=>x=9:3=>x=3

Answer 2

Răspuns:

3x+2(y+1)=7

2(x-5)+3y=-10

3x+2y+2=7

2x-10+3y=-10

3x+2y=7-2

2x+3y=-10+10

3x+2y=5 |×2

2x+3y=0 |×3

6x+4y=10

6x+9y=0

¯¯¯¯¯¯¯¯¯¯¯¯

-5y=10

y=10:(-5)

y=-2

6x+9×(-2)=0

6x-18=0

6x=18

x=18:6

x=3