Question

resolva os sistemas lineares pelo método de substituição:

A)x+y=8
x-y=0

B) x+y=8
-x+y=4

C) 2x+y=4
x-y=5

D) 2x+y=6
x+y=0

E) 2x+y=2
3x+y=4

F) x-y=11
2x-y=7


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Answer 1

A)

X=0+Y

0+Y+Y=8

2Y=8

Y=8/2

Y=4

B)

Y=4+X

X+4+X=8

2X=8-4

2X=4

X=4/2

X=2

C)

X=5+Y

2(5+Y)+Y=4

10+2Y+Y=4

3Y=4-10

3Y=-6

Y=-6/3

Y=-2

D)

X=0-Y

2(0-Y)+Y=6

-2Y+Y=6

-Y=6(1)

Y=-6

E)

Y=4-3X

2X+4-3X=2

-1X=2-4

-X=-2(1)

X=2

F)X=11-Y

2(11-Y)-Y=7

22-2Y-Y=7

-3Y=7-22

-3Y=-15(1)

3Y=15

Y=15/3

Y=5