14-3x+x-4=0

10-2x=0

-2x=-10

x=-10:(-2)

x=5

32x0,99x25x1,25

=(32x1,25)x(0,99x25)

=40x24,75

=990

bằng 990

34×x-25×x+x×1=8600

(34-25+1)×x =8600

10×x=8600

X=8600÷10

X=860

34.x+25.x+1.x=8600
x.(34+25+1)  = 8600
x.100              = 8600
x                     = 8600:100
x                     = 86

X=860

Lời giải:

$2x=3y\Leftrightarrow \frac{x}{3}=\frac{y}{2}\Leftrightarrow \frac{x}{6}=\frac{y}{4}$

$5y=4z\Leftrightarrow \frac{y}{4}=\frac{z}{5}$

Vậy:

$\frac{x}{6}=\frac{y}{4}=\frac{z}{5}$

$\Rightarrow (\frac{x}{6})^3=(\frac{y}{4})^3=(\frac{z}{5})^3=\frac{xyz}{6.4.5}=\frac{120}{120}=1$

$\Rightarrow \frac{x}{6}=\frac{y}{4}=\frac{z}{5}=1$

$\Rightarrow x=6; y=4; z=5$

Ta có: 2x=3y

nên \(\dfrac{x}{3}=\dfrac{y}{2}\)

hay \(\dfrac{x}{6}=\dfrac{y}{4}\)(1)

Ta có: 5y=4z

nên \(\dfrac{y}{4}=\dfrac{z}{5}\)(2)

Từ (1) và (2) suy ra \(\dfrac{x}{6}=\dfrac{y}{4}=\dfrac{z}{5}\)

Đặt \(\dfrac{x}{6}=\dfrac{y}{4}=\dfrac{z}{5}=k\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=6k\\y=4k\\z=5k\end{matrix}\right.\)

Ta có: xyz=120

nên \(120k^3=120\)

\(\Leftrightarrow k^3=1\)

hay k=1

Suy ra: x=6; y=4; z=5

a: =36,5

b: =3,619

a; 3,65 + 3,65 + 8 x 3,65

= 3,65 x 1 + 3,65 x 1  + 8 x 3,65

= 3,65 x (1+ 1+ 8)

= 3,65 x (2 + 8)

= 3,65 x 10

= 36,5

b; 0,125 x 3,619 x 8

= (0,125 x 8) x 3,619

= 1 x 3,619

= 3,619

Theo mk là :

   32 x 0,99 x 25 x 1,25 

= ( 32 x 25 ) x ( 0,99 x 1,25 )

= 800 x 1,2375

= 990

a, 2\(x\) + 4 - 5\(x\) = -11

    -(5\(x\) - 2\(x\)) + 4 = -11

    -3\(x\)         + 4 = -11

     3\(x\)              = 11 + 4

     3\(x\)              = 15

       \(x\)              = 15 : 3

        \(x\)              = 5

b, \(x\) - (-5) = 8

    \(x\) + 5 = 8

    \(x\)       = 8 - 5

    \(x\)       = 3

c, (\(x\) + 2)² = 25

   \(\left[{}\begin{matrix}x+2=5\\x+2=-5\end{matrix}\right.\)

  \(\left[{}\begin{matrix}x=3\\x=-7\end{matrix}\right.\)