bài này hổng có tính đc

\(95-3\cdot\left(x+1\right)=42\)

\(=>3\cdot\left(x+1\right)=95-42\)

\(=>3\cdot\left(x+1\right)=53\)

\(=>x+1=53:3\)

\(=>x+1=\frac{53}{3}\)

\(=>x=\frac{53}{3}-1\)

\(=>x=\frac{53}{3}-\frac{3}{3}\)

\(=>x=\frac{50}{3}\)

95 - 3( x + 1 ) = 42

      3( x + 1 ) = 95 - 42

       3( x + 1 ) = 53

          x + 1    = 53 : 3 

          x  + 1   = 17,66...........67

                 x   = 17,66...........67 - 1

                 x   = 17,66..........66

y = 43 

vì 42,95< 43 < 43,01

 tk tớ nha 

Số tự nhiên x là:

 43 vì 43 là số tự nhiên lớn hơn 42,95 và bé hơn 43,01

  **** nha

Vì 42,95<x<43,1 mà x là số tự nhiên => x=43

\(\left(-95\right)+2\times\left(42-37\right)^2+\left(2018\times2019\right)^0\\ =-95+2\times5^2+1\\ =-94+2\times25\\ =-94+50=-44\)

a, => (x-10/30 - 3) + (x-14/43 - 2) + (x-5/95 - 1) + x-100/8 = 0 ( vì x-148/8 = x-100/8 + 48/8 = x-100/8 + 6 )

=> x-100/30 + x-100/43 + x-100/95 + x-100/8 = 0

=> (x-100).(1/30 + 1/43 + 1/95 + 1/8) = 0

=> x-100 = 0 ( vì 1/30+1/43+1/95+1/8 > 0 )

=> x = 100

Vậy x = 100

Tk mk nha

=> 42.(x-95)=1350-90

=> 42.(x-95)=1260

=> x-95=1260:42

=> x-95=30

=> x=30+95

=> x=125

=> 1350 -42x + 3990 = 90 => -42x = -5250 => x = 125

1350-42.(x-95)=90

        42.(x-95)=1350-90

        42.(x-95)=1260

              x-95 =1260:42

              x-95 =30

              x      =30+95

              x      =125

=> x = 125

a) \(175-\left(42:x+95\right)=3\)

\(\Rightarrow42:x+95=172\)

\(\Rightarrow42:x=77\)

\(\Rightarrow x=42:77\)

\(\Rightarrow x=\dfrac{6}{11}\)

b) \(450:\left(75-13\cdot x\right)=10\)

\(\Rightarrow75-13\cdot x=450:10\)

\(\Rightarrow75-13\cdot x=45\)

\(\Rightarrow13\cdot x=75-45\)

\(\Rightarrow13\cdot x=30\)

\(\Rightarrow x=\dfrac{30}{13}\)

\(3x=2y\Rightarrow\frac{x}{2}=\frac{y}{3}\)

\(7y=5z\Rightarrow\frac{y}{5}=\frac{z}{7}\)

\(\hept{\begin{cases}\frac{x}{2}=\frac{x}{3}\\\frac{y}{5}=\frac{x}{7}\end{cases}\Rightarrow}\frac{x}{2}=\frac{5y}{15};\frac{3y}{15}=\frac{z}{7}\)

\(\Rightarrow\frac{x}{10}=\frac{y}{15}=\frac{z}{21}\)

Áp dụng tính chát dãy tỉ số = nhau ta có:

\(\frac{x}{10}=\frac{y}{15}=\frac{z}{21}=\frac{x-y+z}{10-15+21}=\frac{32}{16}=2\)

\(\Rightarrow\frac{x}{10}=2\Rightarrow x=20\)

\(\frac{y}{15}=2\Rightarrow y=30\)

\(\frac{z}{21}=3\Rightarrow z=63\)

b, Tự làm

c, \(5x=2y\Leftrightarrow\frac{x}{2}=\frac{y}{5}\)

\(2x=3z\Leftrightarrow\frac{x}{3}=\frac{z}{2}\)

\(\Leftrightarrow\frac{x}{2}=\frac{y}{5};\frac{x}{3}=\frac{z}{2}\)

\(\Leftrightarrow\frac{x}{6}=\frac{y}{15}=\frac{x}{6}=\frac{z}{10}\)

\(\Leftrightarrow\frac{x}{6}=\frac{y}{15}=\frac{z}{10}\)

Đặt \(\frac{x}{6}=\frac{y}{15}=\frac{z}{10}=k(k\inℤ)\)

\(\Leftrightarrow\hept{\begin{cases}x=6k\\y=15k\\z=10k\end{cases}}\)

\(\Leftrightarrow x\cdot y=6k\cdot15k=90\)

\(\Leftrightarrow90:k^2=90\Leftrightarrow k^2=1\Leftrightarrow k=\pm1\)

\(\Leftrightarrow\hept{\begin{cases}x=6k\\y=15k\\z=10k\end{cases}}\Leftrightarrow\hept{\begin{cases}x=6\\y=15\\z=10\end{cases}}\)hay \(\hept{\begin{cases}x=-6\\y=-15\\z=-10\end{cases}}\)

Vậy \((x,y)\in(6,15);(-6,-15)\)

d, \(2x=3y=5z\Leftrightarrow\frac{2x}{30}=\frac{3y}{30}=\frac{5z}{30}\)

\(\Leftrightarrow\frac{x}{15}=\frac{y}{10}=\frac{z}{6}\)

Áp dụng tính chất dãy tỉ số bằng nhau ta có :

\(\frac{x}{15}=\frac{y}{10}=\frac{z}{6}=\frac{x+y-z}{15+10-6}=\frac{95}{19}=5\)

Vậy : \(\hept{\begin{cases}\frac{x}{15}=5\\\frac{y}{10}=5\\\frac{z}{6}=5\end{cases}}\Leftrightarrow\hept{\begin{cases}x=75\\y=50\\z=30\end{cases}}\)