Question

saut!puteti rezolva prin medoda substitutiei va rog?pas cu pas ​

Answer 1

Răspuns:

1. S (1,2)

2. S (1,1)

3. S (7/2,4)

Explicație pas cu pas:

1.

(x+2y=5

(x-y= -1

(x= 5-2y

(x-y= -1

(x=5-2y

(5-2y-y= -1

(x=5-2y

(5-3y= -1

(x=5-2y

(-3y= -1-5

(x=5-2y

(-3y=-6/:(-3)

(x=5-2y

(y=2

(x=5-4

(y=2

(x=1

(y=2

2.

(2x -y = 1

(x +3y =4

(2x = 1 + y

(x +3y=4

(x= 1 + y supra 2

(1 + y/2 +3y=4

(x= 1 +y/2

(1 + y +6y=8

(x=1+y/2

(7y= 7/:7

(x=1+y/2

(y=1

(x=1

(y=1

3.

(2x +3y =19

(4x+11y =53

(2x = 19 -3y

(4x+11y=53

(x= 19 -3y/2

(4x+11y=53

(x=19-3y/2

(19-3y/2+11y=53

(x=19-3y/2

(19-3y+22y=106

(x=19-3y/2

(19y=87

(x=19-3y/2

(y=4

(x=19-12/2

(y=4

(x=7/2

(y=4