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estelleluna14
4 tháng trước

Cho hệ phương trình mx + y =3 4x + my = 6 Tìm điều kiện của tham số m để hệ phương trình có nghiệm (x ;y ) thỏa diều kiện x > 2 và y > 0

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nhivh2k8
4 tháng trước

Đáp án:

$\begin{cases} y = 3 - mx\\4x + my = 6\\ \end{cases}$

=> 4x + m(3 - mx) = 6

- m² + 3m + x = 6

x( 1 - m² ) = 6 - 3m

x = $\frac{6 - 3m}{1 - m^2}$ 

=> x = $\frac{3( 2 - m)}{(2 - m )(2+m)}$ = $\frac{3}{2 + m}$ 

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