Respuesta :

CrazyBun
Answer:

Explanation:

11.
x + y = 2 (1)
2x + 7y = 9 (2)
—————-—
-2(x + y = 2)
2x + 7y = 9
——————-
-2x - 2y = -4
2x + 7y = 9
——————-
5y = 5
y = 1

x + y = 2
x + 1 = 2
x = 1

12.
8x - 5y = 11
4x - 3y = 5
——————
8x - 5y = 11
-2(4x - 3y = 5)
———————-
8x - 5y = 11
-8x + 6y = -10
———————-
y = 1

4x - 3y = 5
4x - 3 = 5
4x = 8
x = 2

17.
9x + 2y = 39
6x + 13y = -9
———————
2(9x + 2y = 39)
-3(6x + 13y = -9)
—————————
18x + 4y = 78
-18x - 39y = 27
————————
-35y = 105
y = 105/-35
y = -3

9x + 2y = 39
9x -6 = 39
9x = 45
x = 45/9
x = 5

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