/x + \(\frac{4}{15}\)/ - 3,75 = -2,15

=> /x + \(\frac{4}{15}\)/ = 1,6

=> \(x+\frac{4}{5}=1,6\) hoặc \(x+\frac{4}{5}=-1,6\)

=> \(x=0,8\)hoặc \(x=-2,4\)

c) 22/5 + 51/9 + 11/4 + 3/5 + 1/3 + 1/4
= 22/5 +3/5 +51/9 + 1/3 +11/4+1/4
= (22/5 +3/5) +(51/9 + 3/9) +(11/4+1/4)
= 25/5 +54/9 +12/4
= 5 +6 +3
= 14
d) (1/6 + 1/10 + 1/15) : (1/6 + 1/10 - 1/15) 
= (5/30 + 3/30 +2/30 ) :(5/30 +3/30 -2/30)
= 10/30 : 6/30
= 1/3 : 1/5
= 5/3

\(\left|x+\dfrac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)

\(\Leftrightarrow\left|x+\dfrac{4}{15}\right|=-2,15+3,75\)

\(\Leftrightarrow\left|x+\dfrac{4}{15}\right|=\dfrac{8}{5}\)

\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{4}{15}=\dfrac{8}{5}\\x+\dfrac{4}{15}=-\dfrac{8}{5}\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{4}{3}\\x=-\dfrac{28}{15}\end{matrix}\right.\)

\(\Rightarrow\left|x+\dfrac{4}{15}\right|-3,75=-2,15\\ \Rightarrow\left|x+\dfrac{4}{15}\right|=1,6=\dfrac{8}{5}\\ \Rightarrow\left[{}\begin{matrix}x+\dfrac{4}{15}=\dfrac{8}{5}\\x+\dfrac{4}{15}=-\dfrac{8}{5}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{4}{3}\\x=-\dfrac{28}{15}\end{matrix}\right.\)

\(\left|x+\frac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)

\(\left|x+\frac{4}{15}\right|-3,75=-2,15\)

\(\left|x+\frac{4}{15}\right|=-2,15+3,75\)

\(\left|x+\frac{4}{15}\right|=1,6\)

Ta có 2 trường hợp

trường hợp 1

\(x+\frac{4}{15}=1,6\)

\(x=1,6-\frac{4}{15}\)

\(x=\frac{4}{3}\)

Trường hợp 2

\(x+\frac{4}{15}=-1,6\)

\(x=-1,6-\frac{4}{15}\)

\(x=\frac{-28}{15}\)

Vậy \(x=\left\{-\frac{28}{15};\frac{4}{3}\right\}\)

| x + 4/15 | - | - 3,75 | = - | - 2,15 |

| x + 4/15 | - 3,75      = - 2,15

| x + 4/15 |               = - 2,15 + 3,75

| x + 4/15 |               = 1,6

Trường hợp 1 :  x + 4/15 = 1,6   suy ra x = 4/3

Trương hợp 2:  x + 4/15 = - 1,6 suy ra x = -28/15

b) | x + 415 | - | -3,75| = -(-2,15)

x+4/15=-1.6

\(\left|x+\frac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)

\(\Rightarrow\left|x+\frac{4}{15}\right|-3,75=-2,15\)

\(\Rightarrow\left|x+\frac{4}{15}\right|=-2,15+3,75\)

\(\Rightarrow\left|x+\frac{4}{15}\right|=1,6\)

\(\Rightarrow\left|x+\frac{4}{15}\right|=\frac{8}{5}\)

\(\Rightarrow\left[\begin{array}{nghiempt}x+\frac{4}{15}=\frac{8}{5}\\x+\frac{4}{15}=-\frac{8}{5}\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}x=\frac{4}{3}\\x=-\frac{28}{15}\end{array}\right.\)

Ta có : \(\left|x+\frac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)

\(\Leftrightarrow\left|x+\frac{4}{15}\right|=3,75-2,15=\frac{8}{5}\)

\(\Rightarrow\left[\begin{array}{nghiempt}x+\frac{4}{15}=\frac{8}{5}\\-x-\frac{4}{15}=\frac{8}{5}\end{array}\right.\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x=\frac{4}{3}\\x=-\frac{28}{15}\end{array}\right.\)

| x + 4/15 | - | - 3,75 | = - | - 2,15 |
\(\Rightarrow\)| x + 4/15 | -  3,75  = - 2,15 |

\(\Rightarrow\)| x + 4/15 | =  3,75  +  (- 2,15)

\(\Rightarrow\)| x + 4/15 | =1,6

\(\Rightarrow\)x+4/15=1,6 hoặc x+4/15=-1,6

Ta xét các trường hợp

TH1: x+4/15=1,6\(\Rightarrow\)x=4/3

TH2:x+4/15=-1,6 \(\Rightarrow\)x=-28/15

Vậy x=4/3 hoặc -28/15

|x + 4/15| - |-3,75| = -|- 2,15|

=> |x + 4/15| - 3,75 = 2,15

=> |x + 4/15| = 59/10

=> \(\orbr{\begin{cases}x+\frac{4}{15}=\frac{59}{10}\\x+\frac{4}{15}=-\frac{59}{10}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{169}{30}\\x=\frac{-185}{30}\end{cases}}\)

\(\left|x+\frac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)

\(\left|x+\frac{4}{15}\right|-3,75=-2,15\)

\(\left|x+\frac{4}{15}\right|=-2,15+3,75\)

\(\left|x+\frac{4}{15}\right|=1,6\)

\(\left|x+\frac{4}{15}\right|=\frac{8}{5}\)

\(\Rightarrow\hept{\begin{cases}x+\frac{4}{15}=\frac{8}{5}\\x+\frac{4}{15}=\frac{-8}{5}\end{cases}\Rightarrow\hept{\begin{cases}x=\frac{8}{5}-\frac{4}{15}=\frac{4}{3}\\x=\frac{-8}{5}-\frac{4}{15}=\frac{-28}{15}\end{cases}}}\)

\(\left|x+\frac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)

\(\left|x+\frac{4}{15}\right|-3,75=-2,15\)

\(\left|x+\frac{4}{15}\right|=1,6\)

\(\orbr{\begin{cases}x+\frac{4}{15}=1,6\\x+\frac{4}{15}=-1,6\end{cases}}\)

Còn lại bn tự làm nha