Respuesta :

Answer:

2) y=-1       4)y=-1

Step-by-step explanation

    4x+8y=20

+  -4x+2y=-30

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      10y=-10

isolate y by dividing 10 on each side

     y=-1

    -6x+5y=1

+    6x+4y=-10

----------------------

    9y=-9

y=-1