[Toán 7] Bài toán tìm x

K

kool_boy_98

$a) A=2 \Longleftrightarrow \frac{x-2}{x-5}=2$

$\Longleftrightarrow x-2=2x-10$

$\Longleftrightarrow x=8$

b) Ta có: $\frac{x-2}{x-5}=1+\frac{3}{x-5}$

Để $A \in Z$ thì $(x-5)=Ư_3$

Suy ra ... <Tự làm tiếp>

$c) A>1 \Longleftrightarrow \frac{x-2}{x-5}>1$

$\Longleftrightarrow 1+\frac{3}{x-5} >1$

$\Longleftrightarrow x-5 > 0$

$\Longleftrightarrow x>5$
 
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