Question

cho biết: 12/x = -9/15. Vậy x bằng

A. x = 20

B. x = -20

C. x = 180

d. -3

Answer 1

\(\dfrac{12}{x}=\dfrac{-9}{15}\)
\(\dfrac{12}{x}=\dfrac{-3}{5}\)
\(x=-\dfrac{12\times5}{3}\)
\(x=-20\)

Answer 2

`12/x = -9/15`

`=> -9x=15.12`

`=>-9x=180`

`=> x=180:(-9)`

`=>x= -20`

`->B`

 

Answer 3

`12/x=-9/15`

`=>12*15=-9*x`

`=>-9*x=180`

`=>x=180:(-9)`

`=>x=-20`

`=>B`

Answer 4

\(\dfrac{12}{x}=-\dfrac{9}{15}\)

\(\Rightarrow12.15=9x\)

\(\Rightarrow12.15=-9.\left(-20\right)\)

Vậy chọn phương án B.