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thachdau2k7
1 tuần trước

{ 2x-y=4 { 5x+y=17 giúp

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Doraemon19
1 tuần trước

Đáp án:

Vậy, hệ phương trình đã cho có cặp nghiệm là `(x;y)=(3;2).`

Giải thích các bước giải:

`{(2x-y=4),(5x+y=17):}`

`<=>{(y=2x-4),(5x+2x-4=17):}`

`<=>{(y=2x-4),(7x-4=17):}`

`<=>{(y=2x-4),(7x=21):}`

`<=>{(y=2.3-4),(x=3):}`

`<=>{(y=2),(x=3):}`

Vậy, hệ phương trình đã cho có cặp nghiệm là `(x;y)=(3;2).`

khangninja001
1 tuần trước

Đáp án + Giải thích các bước giải:

$\begin{cases} 2x-y=4\\5x+y=17\end{cases}$

$\begin{cases} y=2x-4\\5x+2x-4=17\end{cases}$

$\begin{cases} y=2x-4\\7x=21\end{cases}$

$\begin{cases} x=3\\y=2\end{cases}$

Vậy pt trên có cặp nghiệm ${(x;y)=(3;2)}$

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