Question

4x-y=11
7x-5y=16

x=2y-1
2x+3y=12

metoda subtitutiei

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Answer 1

Răspuns:

Explicație pas cu pas:

4x-y=11

7x-5y=16

______

y = 4x - 11

7x - 5(4x - 11) = 16

7x - 20x + 55 = 16

-13x + 55 = 16

13x = 55 - 16

13x = 39

x = 39 : 13 = 3

y = 4*3 - 11 = 12 - 11 = 1

________________________

x=2y-1

2x+3y=12

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2(2y - 1) + 3y = 12

4y - 2 + 3y = 12

7y = 12 + 2 = 14

y = 14 : 7 = 2

x = 2*2 - 1 = 4 - 1 = 3