\(\frac{4}{x}=-\frac{y}{6}=0,5\)

=>\(\frac{4}{x}=0,5\)  => x = 4 : 0,5 = 8

=>\(-\frac{y}{6}=0,5\)  => y = 0,5 x (- 6 ) = -3

vậy x = 8

 y  =  -3

1 đúng nhé

\(\frac{4}{x}=0,5\Rightarrow x=4:0,5=8\)

\(-\frac{y}{6}=\frac{y}{-6}=0,5\Rightarrow y=0,5.\left(-6\right)=-12\)

\(\frac{4}{x}=0,5\Rightarrow x=4.0,5=8;-\frac{y}{6}=\frac{y}{-6}=0,5\Rightarrow y=0,5.\left(-6\right)=-3\)

    4/x=0.5

(=)x= 4/0.5

(=)x=8

     -y/6=0.5

(=)-y=0.5*6

(=)-y=3

(=)y=-3

OK?

Xét \(\frac{4}{x}=\frac{-y}{6}\Leftrightarrow\frac{4.6}{6x}=\frac{x.\left(-y\right)}{6x}\Leftrightarrow\frac{24}{6x}=\frac{x.\left(-y\right)}{6x}\)

suy ra 24 = x.(-y)    (1)

Do \(\frac{4}{x}=0,5\) nên \(\frac{4}{x}=\frac{0,5x}{x}\) => 4 = 0,5 x => x = 4 : 0,5 => x = 8    (2)

Từ (1) và (2) suy ra (-y).8 = 24    =>   -y = 24 : 8   => -y = 3 => y= -3

       Kết luận : x = 8 ; y = -3

x=8

y= -3  

Lưu ý -(-3)=3 

Lik nhé                                                   

a) y : 0,25 + y x 8 - y : 0,5 = 230

y x 4 + y x 8 - y x 2 = 230

y x (4 + 8 - 2) = 230

y x 10 = 230

y = 230 : 10

y = 23

b) \(x\) x 4 + \(x\) x 6 = 30

\(x\) x (4 + 6) = 30

\(x\) x 10 = 30

\(x\) = 30 : 10

\(x\) = 3

a; y :0,25 + y x 8 - y: 0,5 = 230

    y x 4 + y x 8 - y x 2 = 230

    y x (4 + 8 - 2) = 230

    y x 10 = 230

     y = 230 : 10

     y = 23

b; \(x\) \(\times\) 4 + \(x\) \(\times\) 6 = 30

    \(x\) \(\times\) (4 + 6) = 30

     \(x\) \(\times\) 10 = 30

     \(x\)           = 30 : 10

      \(x\)          = 3

\(7,75-\left(0,5\times y\div5-6,2\right)=5\)

\(0,5\times y\div5-6,2=7,75-5=2,75\)

\(0,5\div5\times y-6,2=2,75\)

\(0,1\times y=2,75+6,2=8,95\)

\(\dfrac{1}{10}y=8,95\)

\(y=8,95\times10=89,5\)

\(y\div6\times7,2+1,3\times y+y\div2+15=19,95\)

\(1,2\times y+1,3\times y+0,5y=19,95-15=4,95\)

\(y\left(1,2+1,3+0,5\right)=4,95\)

\(2y=4,95\)

\(y=4,95\div2=2,475\)