Question

a) 3×+ 4y =19
2× -3y =7


b) 3× + 4y = -5
×-2y =5

c)× + y =6
2× -y =14

d)× + 24y =5
× + 3y =8

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Answer 1

Resposta:

Explicação passo a passo:

A)

3×+ 4y =19 (3)

2× -3y =7 (4)

9x + 12y = 57

8y - 12y = 28 (+)

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

17y = 85

Y = 85/17

Y = 5

3x + 4y = 19

3x + 4.5 = 19

3x + 20 = 19

3x = 19 - 20

3x = - 1

x = - 1/3

_______

b)

3× + 4y = -5

× -2y =5 (2)

3x + 4y = - 5

2x - 4y = 10 (+)

______________

5x = 5

X = 5/5

X = 1

X - 2y = 5

1 - 5 = 2y

- 4 = 2y

2y = - 4

y = -4/2

y = - 2

c)

× + y =6

2× -y =14(+)

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

3x = 20

x = 20/3

x + y = 6

20/3 + y = 6

y = 6 - 20/3

y = (3.6 - 20)/3

y = (18 - 20)/3

y = - 2/3

d)

× + 24y =5

× + 3y =8 (-1)

x + 24y = 5

- x - 3y = - 8 (+)

____________

21y = - 3 (:3)

7y = - 1

y = - 1/7

X + 3y = 8

x + 3.(-1/7) = 8

X - 3/7 = 8

X = 8 + 3/7

X = (7.8+3)/7

X = (56+3)/7

X = 59/7