Question

Rezolva prin metoda reducerii urmatoarele sisteme

(c, h) dau coroana si 30 de puncte​

Answer 1

c) 2x + 3y = -2 /×(-3)

3x + 4y = -1 /×2

-6x - 9y = 6

6x + 8y = -2

Adunam cele două relatii:

-6x -9y + 6x + 8y = 6 - 2

-y = 4

y = -4

2x + 3y = -2

2x +3×(-4) = -2

2x - 12 = -2

2x = -2 + 12 = 10

x = 10 : 2

x = 5

R: x = 5, y = -4

h) 2x + 3y = 14 / ×(-2)

4x - 5y = 6

-4x - 6y = -28

4x - 5y = 6

Adunam cele două relatii:

-4x - 6y + 4x - 5y = -28 + 6

-11y = -22

y = (-22)/(-11)

y = 2

2x + 3y = 14

2x + 3×2 = 14

2x + 6 = 14

2x = 14 - 6 = 8

x = 8 : 2

x = 4

R: x = 4, y = 2