Question

4. Resolva este sistema de equações:
14(x + 2y) = 7(2x + y) + 5
13x - 5y + 11 = 4(5x – 2y).

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Answer 1

14(x + 2y) = 7(2x + y) + 5

13x - 5y + 11 = 4(5x – 2y)

14x + 28y = 14x + 7y + 5

13x - 5y + 11y = 20x - 8y

14x - 14x + 28y - 7y = 5

21y = 5

y = 5/21

13x - 5y + 11 = 20x - 8y

13x - 5(5/21) + 11= 20x - 8(5/21)

13x - 25/21 + 11 = 20x - 40/21

273x/21 - 25/21 + 231/21 = 420x/21 - 40/21

273x - 25 + 231 = 420x - 40

420x - 273x = - 25 + 231 + 40

147x = 246

x = 246/147

x = 82/49

Resposta: ( 82/49,  5/21 ).