y : 8 + y x 56,78 = 138,22

y x 0,125 + y x 56,78 = 138,22 ( chuyển : 8 sang x 0,125 vì 8 x 0,125 = 1)

 y x ( 0,125 + 56,78 ) = 138,22

                 y x 56,905 = 138,22

                             y    = 138,22 : 56,905

                             y    = ( tự tính nha)

\(y:8+y.56,78=69,11.2\)

\(y.0,125+y.56,78=138,22\)

\(y.\left(0,125+56,78\right)=138,22\)

\(y.56,905=138,22\)

                 \(y=138,22:56,905\)

                 y=(tự tính)

y: 8 + y x 8 - 56,78 = 69,11 x 2  

yx1/8+yx8-56,78=69,11x2

yx(1/8+8)-56,78=138,22

yx8,125=138,22+56,78

yx8,125=195

y=195:8,125

y=24

y=24 nha

y bằng 24 nha bạn

Ta có:
\(\frac{x+3}{y+5}=\frac{x+5}{y+7}\)
\(\Rightarrow\left(x+3\right)\left(y+7\right)=\left(x+5\right)\left(y+5\right)\)
\(\Rightarrow xy+7x+3y+21=xy+5x+5y+25\)
\(\Rightarrow\left(7x-5x\right)+\left(3y-5y\right)=25-21\)
\(\Rightarrow2x-2y=4\)
\(\Rightarrow2\left(x-y\right)=4\)
\(\Rightarrow x-y=2\)
Thử lại: Do \(x-y=2\Rightarrow x=y+2\) nên ta có:
\(\frac{\left(y+2\right)+3}{y+5}=\frac{\left(y+2\right)+5}{y+7}\)
\(\Rightarrow\frac{y+5}{y+5}=\frac{y+7}{y+7}\)
\(\Rightarrow1=1\) ( thoả mãn )
Vậy hiệu giữa x và y là 2

\(\frac{3x}{5}=\frac{-30}{50}\)

\(\Rightarrow\frac{3x}{5}=\frac{-3}{5}\)

\(\Rightarrow3x.5=\left(-3\right).5\)

\(\Rightarrow15x=\left(-15\right)\)

\(\Rightarrow x=\left(-15\right):15=-1\)

\(\frac{-6}{y}=\frac{-30}{50}\)

\(\Rightarrow\frac{-6}{y}=\frac{-3}{5}\)

\(\Rightarrow\left(-6\right).5=-3y\)

\(\Rightarrow\left(-30\right)=-3y\)

\(\Rightarrow y=\left(-30\right):\left(-3\right)=10\)

Vậy x = -1; y = 10

\(\frac{3x}{5}=\frac{-6}{y}=\frac{-30}{50}\)

rút gọn:\(\frac{-30}{50}=\frac{-3}{5}\)

ta có:\(\frac{3x}{5}=\frac{-3}{5}\)=>3x.5=-15

                                     15x=-15=>x=-1

\(\frac{-6}{y}=\frac{-3}{5}\)=>-30=-3y

                              10=y

vậy x=-1, y=10

\(\frac{3x}{5}=\frac{-6}{y}=\frac{-30}{50}\)

\(\Rightarrow\frac{3x}{5}=\frac{-6}{y}=\frac{-3}{5}\)

+)\(\frac{3x}{5}=\frac{-3}{5}\)

\(\Rightarrow\)3x*5=-15\(\Rightarrow\)3x=-3\(\Rightarrow\)x=-1

+)\(\frac{-6}{y}=\frac{-3}{5}\)

\(\Rightarrow\)-3y=-30\(\Rightarrow\)y=10

Vậy x= -1 và y=10

 Y : 0,25 + Y x 8 + Y : 0,5 = 0,14

=>Y :\(\frac{1}{4}\)+ Y x 8 + Y :\(\frac{1}{2}\)=0,14

==>Y x 4+ Y x 8 + Y x 2=0,14

==>Y x(4+8+2)=0,14

         Y x 14=0,14

 ==>Y=0,14:14

            Y=0,01

\(y:0,25+y\cdot8+y:0,5=0,14\)

\(\Leftrightarrow y\cdot4+y\cdot8+y\cdot2=0,14\)

\(\Leftrightarrow y\left(4+8+2\right)=0,14\)

\(\Leftrightarrow y\cdot14=0,14\)

\(\Leftrightarrow y=0,01\)

Ta có :

  Y : 0,25 + Y x 8 + Y : 0,5 = 0,14

  Y x 4  + Y x 8 + Y x 2 = 0,14

  Y x ( 4 + 8 + 2 ) = 0,14

  Y x 14 = 0,14 

  Y = 0,14 : 14

  Y = 0,01

Hok tốt !

Gọi số cần tìm là x

Theo đề bài ta có

x-8=16+27

x-8=43

X=43+8

X=51

Vậy x=51

bang 51

51 nha em