Question

Resolva os sistemas pelo metodo da adiçao

Answer 1

Resposta:

a-

2x=14

x=7

y=4

b-

-x=2

x= -2

y=8

c-

x=1

y=2

d-

2x=-1

x= -0,5

y= -6,5

Explicação passo-a-passo:

Answer 2

a)

{x+y=11

{x-y=3

$2x = 14 \\ x = \frac{14}{2} \\ x = 7$

$x + y = 11 \\ 7 + y = 11 \\ y = 11 - 7 \\ y = 4$

s={7,4}

b)

{x+y=6 ×(-1)

{2x+y=4

{-x-y=-6

{2x+y=4

$x = - 2 \\ x + y = 6 \\ - 2 + y = 6 \\ y = 6 + 2 \\ y = 8$

s={-2,8}

c) {3x+y=5

{2x+y=4×(-1)

{3x+y=5

{-2x-y=-4

$x = 1 \\ 3x + y = 5 \\ 3.1 +y = 5 \\ 3 + y = 5 \\y= 5 - 3 \\ y = 2$

s={1,2}

d)

{x-y=6

{x+y=-7

$2x = - 1 \\ x = - \frac{1}{2}$

$x + y = - 7 \\ - \frac{1}{2} + y = - 7 \\ y = \frac{1}{2} - 7 \\ y = \frac{1 - 14}{2} = - \frac{13}{2}$

s={-½, -13/2}

e)

{x=5-3y

{2x-y=-4

{x+3y=5

{2x-y=-4×(3)

{x+3y=5

{6x-3y=-12

$7x = - 7 \\ x = - \frac{7}{7} \\ x = - 1$

$x + 3y = 5 \\ - 1 + 3y = 5 \\ 3y = 5 + 1 \\ 3y = 6 \\ y = \frac{6}{3} = 2$

S={-1,2}

f)

{x-3=-y

{3x+2=y+3

{x+y=3

{3x-y=3-2

{x+y=3

{3x-y=1

$4x = 4 \\ x = \frac{4}{4} \\ x = 1$

$x + y = 3 \\ 1 + y = 3 \\ y = 3 - 1 \\ y = 2$

S={1,2}