Question

daca 3x+5y=55 si 2x+2y=26 aflati x si y
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Answer 1

Răspuns:

2x+2y=26 | :2

x+y=13

x=13-y

3(13-y)+5y=55

39-3y+5y=55

2y=16

y=8

x+8=13

x=5

Answer 2

Raspuns:

$x=5$

$y=8$

Explicatie pas cu pas:

$3x+5y=55$

$2x+2y=26$⇒$2(x+y)=26|:2$⇒$x+y=13$

$x+y=13$⇒$y=13-x$

$3x+5y=55$⇒$3x+5(13-x)=55$

⇒$3x+65-5x=55$

⇒$-2x+65=55$

⇒$-2x=55-65$

⇒$-2x=-10|:2$

⇒$x=5$

⇒$y=13-x=13-5=8$

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