Question

resolva os sistemas
a) {x+y=7
{x-y=5

b) {2x+y=10
{x+y=6

c) {x+2y=5
{2x+y=10

d) {x+2y=12
{2x-3y=3

Answer 1

a) x+y= 7
x-y= 5
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2x= 12
x= 12/2
x= 6
y= 7-x
x= 7-6= 1
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b) 2x+y= 10
x+y= 6x(-1)
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2x+y= 10
-x-y= -6
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x = 4
y= 6-x
y= 6-4= 2
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c) x+2y= 5
2x+y= 10x(-2)
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x+2y= 5
-4x -2y= -20
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-3x= -15
x= -15/-3
x= 5
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x+2y= 5
5+2y=5
2y= 5-5
2y= 0
y= 0/2= 0
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d) x+ 2y= 12x(-2)
2x-3y= 3
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-2x-4y= -24
2x -3y= 3
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-7y= -21x(-1)
7y= 21
y= 21/7
y= 3
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x+2y= 12
x= 12-2y
x= 12-2*3
x= 12-6=6
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