a,2,5-x=1,3

x=2,5-1,3

x=1,2

b,x-3,5=7,5

x=7.5+3,5

x=11

c,(x-1,5)-2,5=0

x-1,5=2,5

x=2,5+1,5

x=4

d,1,6-(x-0,2)=0

x-0,2=1,6

x=1,6+0,2

x=1,8

A=(3,7- -x)+2,5

vì 2,5>=0 với mọi x

=> x=-1,2

B= (x+1,5)-4,5

Vì -4,5<=0 với mọi x

=> x=-6

Học Tốt

Th1
x-1,5+2,5-x=0
<=>0x=-1
=> vô lí
Th2
-x+1,5-2,5+x=0
<=>0x=1
=>vô lí

vậy không có x thỏa mãn

\(a,x+3,79=15,12\)\(\Rightarrow x=15,12-3,79\)\(\Rightarrow x=11,33\)

\(b,12,1-x=5,49\)\(\Rightarrow x=12,1-5,49\Rightarrow x=6,61\)

\(c,60,45:x=1,5\)\(\Rightarrow x=60,45:1,5\Rightarrow x=40,3\)

\(d,3,5.x-1,5.x=12,5\)

\(\Rightarrow x\left(3,5-1,5\right)=12,5\)

\(\Rightarrow x.2=12,25\Rightarrow x=12,25:2=6,125\)

\(d,12,5.x-2,5.x-50=2,5.10\)

\(\Rightarrow12,5.x-2,5.x-50=25\)

\(\Rightarrow x\left(12,5-2,5\right)=25+50\)

\(\Rightarrow x.10=75\)

\(\Rightarrow x=75:10=7,5\)

a) x=11,33                  b) x=6,61                  c)40,3

     Mình chỉ biết làm tới đó thôi. xin lỗi nha

a, x + 3,79 = 15,12

=> x = 11, 33

vậy_

b, 12,1 - x = 5,49

=> x = 6,61

vậy_

c, 60,45 : x = 1,5

=> x = 40,3

vậy_

d, 3,5.x - 1,5.x = 12,5

=>x(3,5 - 1,5) = 12,5

=> x.2 = 12,5

=> x = 6,25

vậy_

đ, 12,5.x - 2,5.x - 50 = 2,5.10

=> x(12,5 - 2,5) - 50 = 25

=> x.10 = 75

=> x = 7,5

vậy_

\(x.2,5-x.1,5=5\)

\(x.\left(2,5-1,5\right)\)\(=5\)

\(x.1=5\)

\(x=5:1\)

\(x=5\)

x . (2,5 - 1,5)=5

x . 1 = 5

x = 5:1

x = 5

\(x\times2,5-x\times1,5=5\)

  \(x\times\left(2,5-1,5\right)=5\)

                        \(x\times1=5\)

                                \(x=5:1\)

                                  \(x=5\)

mik nhah nhất đó

a)  8,8 : 2,5 + 7,6 : 2,5 - 6,4 : 2,5

= (8,8 + 7,6 - 6,4) : 2,5

= 10 : 2,5

= 4

\(a.\)

\(8.8:2.5+7.6:2.5-6.4:2.5\)

\(=\left(8.8+7.6-6.4\right):2.5\)

\(=10:2.5\)

\(=4\)

\(b.\)

\(0.25\times1200+125\times1.5\times2-250\times2.6\)

\(=250\times1.2+250\times1.5-250\times2.6\)

\(=250\times\left(1.2+1.5-2.6\right)\)

\(=250\times0.1=25\)

\(c.\)

\(\left(32\times11-3200\times0.1-32\right):\left(81.6\times27.3-17.3\times81.6\right)\)

\(=\left[32\times\left(11-10-1\right)\right]:\left[81.6\times\left(27.3-17.3\right)\right]\)

\(=0\)

\(\left|2.5-x\right|=1.3\)

\(\Rightarrow\begin{cases}2.5-x=1.3\\2.5-x=-1.3\end{cases}\Rightarrow\begin{cases}x=1.2\\x=3.8\end{cases}\)

1,6 - | x - 0,2 | = 0

| x - 0,2 |=16

\(=>\left\{{}\begin{matrix}x-0,2=16\\x-0,2=-16\end{matrix}\right.=>\left\{{}\begin{matrix}x=16,2\\x=-15,8\end{matrix}\right.\)

Vậy x=\(\left\{{}\begin{matrix}16,2\\-15,8\end{matrix}\right.\)

a)\(\left|x-3,5\right|=0,25\)

\(\Leftrightarrow\orbr{\begin{cases}x-3,5=0,25\\x-3,5=-0,25\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3,75\\x=3,25\end{cases}}}\)

b)\(\left|1,5-x\right|=1,75\)

\(\Leftrightarrow\orbr{\begin{cases}1,5-x=1,75\\1,5-x=-1,75\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-0,25\\x=3,25\end{cases}}}\)

c)\(\left|x-1,5\right|=1,5\)

\(\Leftrightarrow\orbr{\begin{cases}x-1,5=1,5\\x-1,5=-1,5\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3\\x=0\end{cases}}}\)

d)\(\left|x-2,5\right|+\left|x+1,5\right|=3\)

\(\Leftrightarrow\left|x-2,5\right|+x+1,5=3\)

\(\Leftrightarrow\left|x-2,5\right|=1,5-x\)

\(\Leftrightarrow\orbr{\begin{cases}x-2,5=1,5-x\\x-2,5=x-1,5\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=\varnothing\end{cases}}}\)

=> X x ( 1,5 + 1 + 2,5 ) = 25

=> X x 5 = 25

=> X = 25 : 5

=> X = 5 (tm)

Ai k mk mk k lại !!

X x 1,5 + X + X x 2,5 =25 

=X x (1,5+1+2,5)

X x 5=25

X=25:5

X=5

X x ( 1,5 + 1 + 2,5 ) = 25

X x 5                      = 25

X                            = 25 : 5

X                            = 5

Vậy X = 5