Question

X+Y=3
2X+Y=2

2X+Y=1
-2X+3Y=19

7X-15Y=1
-X-6Y=8

Answer 1

A)

X+Y=3               //-1

2X+Y=2

-x-y=3

2X+Y=2

-----------

x=5 ; y =-2

B)

2X+Y=1

-2X+3Y=19

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

4y = 20

x= -2 ; y=5

C)

7X-15Y=1

-X-6Y=8             //7

7X-15Y=1

-7X-42Y=56

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-57Y = 57

x= -2    ; y = -1