Question

x+y=3
2x -3y=4




6x+2y=25
7x+3y=20



5x-3y=1
4x+7y=5 ajudem a resolver pfvr!!!!!​

Answer 1

Resposta passo a passo:

x + y = 3

2x - 3y = 4

x + y = 3

x = 3 - y

2x - 3y = 4

2(3 - y) - 3y = 4

6 - 2y - 3y = 4

6 - 5y = 4

6 = 4 + 5y

6 - 4 = 5y

2 = 5y

5y = 2

y = 2/5

x = 3 - y

x = 3 - 2/5

x = 15/5 - 2/5

x = (15 - 2)/5

x = 13/5

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6x + 2y = 25

7x + 3y = 20

6x + 2y = 25

2y = 25 - 6x

y = (25 - 6x)/2

7x + 3y = 20

7x + 3((25 - 6x)/2) = 20

7x + (75 - 18x)/2 = 20

(14x)/2 + (75 - 18x)/2 = 20

(14x + 75 - 18x)/2 = 20

14x + 75 - 18x = 20 • 2

14x + 75 - 18x = 40

14x + 75 = 40 + 18x

75 - 40 = 18x - 14x

35 = 4x

4x = 35

x = 35/4

y = (25 - 6x)/2

y = (25 - 6(35/4))/2

y = (25 - (210/4))/2

y = (50/2 - 105/2)/2

y = ((50 - 105)/2)/2

y = (50 - 105)/(2 • 2)

y = - 55/4

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5x - 3y = 1

4x + 7y = 5

5x - 3y = 1

5x = 3y + 1

x = (3y + 1)/5

4x + 7y = 5

4((3y + 1)/5) + 7y = 5

(12y + 4)/5 + 7y = 5

(12y + 4)/5 + (35y)/5 = 5

(12y + 4 + 35y)/5 = 5

12y + 4 + 35y = 5 • 5

12y + 35y + 4 = 25

47y + 4 = 25

47y = 25 - 4

47y = 21

y = 21/47

x = (3y + 1)/5

x = (3(21/47) + 1)/5

x = ((63/47) + 1)/5

x = (63/47 + 47/47)/5

x = ((63 + 47)/47)/5

x = (110/47)/5

x = 110/(47 • 5)

x = 110/(5 • 47)

x = (110/5)/47

x = 22/47