Question

Tìm x biết 18/x=-42/-49

Answer 1

\(\dfrac{18}{x}=\dfrac{-42}{-49}\)

⇔18.(-49)=-42x

⇔-822=-42x

⇔x=21

Answer 2

Có:

\(\dfrac{18}{x}\)=\(\dfrac{42}{49}\)

<=>18x49=x.42

<=>882=x.42

<=>x=882:42

=>x=21

Vậy x là 21

Answer 3

Ta có: \(\dfrac{18}{x}=\dfrac{-42}{-49}\)

\(\Leftrightarrow\dfrac{18}{x}=\dfrac{6}{7}\)

\(\Leftrightarrow x=\dfrac{18\cdot7}{6}=3\cdot7=21\)

Vậy: x=21