Toán {x+y =40 {(x+3)(y+5)=xy+195 giải hộ mk vs ạ 12/10/2021 By Claire {x+y =40 {(x+3)(y+5)=xy+195 giải hộ mk vs ạ
$\begin{cases}x +y=40\\(x+3)(y+5)=xy+195\end{cases}$ `⇒`$\begin{cases}x +y=40\\x y+5x+3y+15=xy+195\end{cases}$ `⇒`$\begin{cases}x +y=40\\5x+3y=180\end{cases}$ `⇒`$\begin{cases}3x +3y=120(1)\\5x+3y = 180(2)\end{cases}$ `(2)-(1)=180-120` `⇒2x=60` `⇒x=30` `⇒y=40-30=10` Trả lời
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$\begin{cases}x +y=40\\(x+3)(y+5)=xy+195\end{cases}$
`⇒`$\begin{cases}x +y=40\\x y+5x+3y+15=xy+195\end{cases}$
`⇒`$\begin{cases}x +y=40\\5x+3y=180\end{cases}$
`⇒`$\begin{cases}3x +3y=120(1)\\5x+3y = 180(2)\end{cases}$
`(2)-(1)=180-120`
`⇒2x=60`
`⇒x=30`
`⇒y=40-30=10`