Question

va rog mult imi trebuie maine​

Answer 1

Răspuns:

a) x = -2; y = 1; b) x = -2; y = -1;

c) x = 1; y = 3; d) x = -3; y = 1

Explicație pas cu pas:

a)

$- x + 4y = 6 | \times (2)| \\ 2x + 7y = 3 \\ \\ - 2x + 8y = 12 \\ 2x + 7y = 3 \\ \\ 15y = 15 = > y = 1 \\ - x + 4 = 6 \\ - x = 2 = > x = - 2$

b)

$3x + 5y = - 11 | \times (2)| \\ - 2x - 7y = 11 | \times (3)| \\ \\6x + 10y = - 22 \\ - 6x - 21y = 33 \\ \\ - 11y = 11 = > y = - 1 \\ 3x - 5 = - 11 \\ 3x = - 6 = > x = - 2$

c)

$11x + 3y = 20 | \times (5)| \\ - 2x + 5y = 13 | \times ( - 3)| \\ \\ 55x + 15y = 100 | \times (5)| \\ 6x - 15y = - 39 | \times ( - 3)| \\ \\ 61x = 61 = > x = 1 \\ 11 + 3y = 20 \\ 3y = 9 = > y = 3$

d)

$6x - 5y = - 23 \\ 2x + 3y = - 3 | \times ( - 3)| \\ \\6x - 5y = - 23 \\ - 6x - 9y = 9 \\ \\ - 14y = - 14 = > y = 1 \\ 6x - 5 = - 23 \\ 6x = - 18 = > x = - 3$