Rozwiązane

L Rozwiaz układ równań metodę przeciwnych współczynników. a) 2 x + y=3 oraz 5x + 4y = 6 b) 3x - 2y = 10 oraz 2x+3y=-2​

Odpowiedź :

Joasia615viz

a) {2x + y = 3 |•(-4)

 {5x + 4y = 6

{-8x - 4y = -12

{5x + 4y = 6

+__________

-3x = -6 |:(-3)

x = 2

{2x + y = 3

{x = 2

{x = 2

{2•2 + y = 3

{x = 2

{4 + y = 3

{x = 2

{y = 3 - 4

{x = 2

{y = -1

b) {3x - 2y = 10 |•3

 {2x + 3y = -2 |•2

{9x - 6y = 30

{4x + 6y = -4

+_________

13x = 26 |:13

x = 2

{3x - 2y = 10

{x = 2

{x = 2

{3•2 - 2y = 10

{x = 2

{6 - 2y = 10

{x = 2

{-2y = 10 - 6

{x = 2

{-2y = 4 |:(-2)

{x = 2

{y = -2