Question

Efetue os sistemas pelo método da adição
A ) X+y: 10
X-y: 4

B ) 5×-y:4
-2×+y:5

C ) X+2y:7
X-2y : -5

Answer 1

A)

x+y=10

x-y=4

x-y=4

x=4+y

x+y=10

4+y+y=10

y+y=10-4

2y=6

y=6/2

y=3

x-y=4

x-3=4

x=4+3

x=7

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B)

5x-y=4

-2x+y=5

5x-y=4

-y=4-5x .(-1)

y=-4+5x

-2x+y=5

-2x+1.(-4+5x)=5

-2x-4+5x=5

-2x+5x=5+4

3x=9

x=9/3

x=3

5x-y=4

5.3-y=4

15-y=4

-y=4-15

y=11

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

C)

x+2y=7

x-2y=-5

x+2y=7

x=7-2y

x-2y=-5

7-2y-2y=-5

-4y=-5-7 .(-1)

4y=12

y=12/4

y=3

x+2y=7

x+2.3=7

x+6=7

x=7-6

x=1