`75 xx 1/x + 25 xx 1/x = 10`

`1/x xx (75+25) = 10`

`=> 1/x xx 100 = 10`

`=> 1/x = 10/100`

`=> 1/x = 1/10`

`=> x = 10`.

=>100:x=10

hay x=10

`x : 75 : x + 25 : x = 10`

`x : 100 = 10`

`x = 10xx100`

`x = 1000`

\(\frac{2}{x}=\frac{y}{15}=\frac{\left(-25\right)}{75}\)

\(\Rightarrow\frac{y}{15}=\frac{\left(-1\right)}{3}\)

\(\frac{y}{15}=\frac{\left(-5\right)}{15}\)

\(\Rightarrow15y=15\times\left(-5\right)\)

\(15y=\left(-75\right)\)

\(y=\left(-75\right)\div15\)

\(y=\left(-5\right)\)

\(\Rightarrow\frac{2}{x}=\frac{\left(-5\right)}{15}\)

\(\frac{2}{x}=\frac{\left(-1\right)}{3}\)

\(\Rightarrow-x=3\times2\)

\(-x=6\)

\(x=\left(-6\right)\)

\(V\text{ậy}x=\left(-6\right);y=\left(-5\right)\)

=>

\(\frac{x+2}{10^{10}}+\frac{x+2}{10^{11}}-\frac{x+2}{12^{12}}-\frac{x+2}{13^{13}}=0\)

=>\(\left(x+2\right)\left(\frac{1}{10^{10}}+\frac{1}{10^{11}}-\frac{1}{12^{12}}-13^{13}\right)=0\)

vì \(\frac{1}{10^{10}}+\frac{1}{10^{11}}-\frac{1}{12^{12}}-\frac{1}{13^{13}}\ne0\)

=>x+2=0=>x=-2

100 - 50:(x-4)=75

50:(x-4)= 100 - 75

50:(x-4)=25

x-4= 50:25

x-4=2

x=2+4

x=6

6 nhaa

\(100-50:\left(x-4\right)=75\)

\(50:\left(x-4\right)=100-75\)

\(50:\left(x-4\right)=25\)

\(x-4=50:25\)

\(x-4=2\)

\(x=2+4\)

\(x=6\)

a) \(\left|x\right|=10\)

\(\Rightarrow\left[{}\begin{matrix}x=10\\x=-10\end{matrix}\right.\)

b) \(\left|x+7\right|=-5\)

Mà: \(\left|x+7\right|\ge0\forall x\)

\(\Rightarrow\) Không tìm được giá trị nào của \(x\) thoả mãn yêu cầu đề bài.

`2,4 xx 25 + 102 xx 9,4 - 9,4 - 9,4`

`=2,4xx25+9,4xx(102-1-1)`

`=2,4xx25+9,4xx100`

`=2,4xx25+940`

`=60+940`

`=1000`

= 2,4 x 25 + ( 102 - 1 - 1) x 9,4 

= 2,4 x 25 + 100 x 9,4 

= 60 + 940 

= 1000

\(2,4.25+102.9,4-9,4-9,4\)

\(=\left(2,4.25\right)+102.9,4-9,4.2\)

\(=60+9,4.\left(102-2\right)\)

\(=60+9,4.100\)

\(=60+940\)

\(=1000\)

= 1.2.3.(1+2+5) / 2.3.5.(1+2+5)

= 1.2.3/2.3.5 = 1/5

Ta có : 1.2.3.(1+2^3+5^3)/2.3.5.(1+2^3+5^3) = 1.2.3/2.3.5 = 1/5