\(C=\left(\dfrac{15-\sqrt{x}}{x-25}+\dfrac{2}{\sqrt{x}+5}\right):\dfrac{\sqrt{x}+1}{\sqrt{x}-5}\left(đk:x\ge0,x\ne25\right)\)

\(=\dfrac{15-\sqrt{x}+2\left(\sqrt{x}-5\right)}{\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}.\dfrac{\sqrt{x}-5}{\sqrt{x}+1}\)

\(=\dfrac{\sqrt{x}+5}{\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}.\dfrac{\sqrt{x}-5}{\sqrt{x}+1}=\dfrac{1}{\sqrt{x}+1}\)

\(ĐK:x\ge0;x\ne25\)

\(C=\dfrac{15-\sqrt{x}+2\sqrt{x}-10}{\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}\cdot\dfrac{\sqrt{x}-5}{\sqrt{x}+1}\\ C=\dfrac{\sqrt{x}+5}{\left(\sqrt{x}+5\right)\left(\sqrt{x}+1\right)}=\dfrac{1}{\sqrt{x}+1}\)

= -15 - x + 25 +x = 10

(-15)+ (-x)+ (-25)+ (-x)

25 - ( 15 - x + 303) + 303 = 25 - 15 + (303 - 303) + x = x + 10

A = ( 71 + x ) - ( -24 - x ) + ( -35 - x )

= 71 + x - ( -24 ) + x + ( -35 ) + x 

= 71 - ( -24 ) + ( -35 ) + x . 3

= 60 + 3x 

= 3 ( 20 + x ) 

B = x - 34 - [ ( 15 + x ) - ( 23 - x ) ]

= x - 34 - [ 15 + x - 23 + x ]

= x - 34 - ( 15 - 23 ) - 2x

= x - 34 - ( -8 ) - 2x

= x - 26 - 2x 

= ( -x )  - 26 

C ) tương tự 

a. x+60

b. -x-26

c.10

P = ( - 15 + | x | ) + ( 25 - |  - x | )

P = ( - 15 + x ) + ( 25 - x )

P = - 15 + x + 25 - x

P = - 15  + 25 + x - x

P = 25 - 15 + 0

P = 10

P=(-15)+x+25-x

P=[(-15)+25]+(x-x)

P=10+0

P=10

\(B=\left(\dfrac{15-\sqrt{x}}{x-25}+\dfrac{2}{\sqrt{x}+5}\right):\dfrac{\sqrt{x}+3}{\sqrt{x}-5}\left(đk:x\ne25,x\ge0\right)\)

\(=\dfrac{15-\sqrt{x}+2\left(\sqrt{x}-5\right)}{\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}.\dfrac{\sqrt{x}-5}{\sqrt{x}+3}=\dfrac{15-\sqrt{x}+2\sqrt{x}-10}{\left(\sqrt{x}+5\right)\left(\sqrt{x}+3\right)}=\dfrac{\sqrt{x}+5}{\left(\sqrt{x}+5\right)\left(\sqrt{x}+3\right)}=\dfrac{1}{\sqrt{x}+3}\)

Ta có: \(B=\left(\dfrac{15-\sqrt{x}}{x-25}+\dfrac{2}{\sqrt{x}+5}\right):\dfrac{\sqrt{x}+3}{\sqrt{x}-5}\)

\(=\dfrac{15-\sqrt{x}+2\sqrt{x}-10}{\left(\sqrt{x}+5\right)\cdot\left(\sqrt{x}-5\right)}\cdot\dfrac{\sqrt{x}-5}{\sqrt{x}+3}\)

\(=\dfrac{1}{\sqrt{x}+3}\)

A) \(\sqrt{25x-25}-\dfrac{15}{2}\sqrt{\dfrac{x-1}{9}}=6+\sqrt{x-1}\)

\(\Leftrightarrow5\sqrt{x-1}-\dfrac{15}{2}\dfrac{\sqrt{x-1}}{3}-\sqrt{x-1}=6\)

\(\Leftrightarrow5\sqrt{x-1}-\dfrac{5}{2}\sqrt{x-1}-\sqrt{x-1}=6\)

\(\Leftrightarrow\dfrac{3}{2}\sqrt{x-1}=6\)

\(\Leftrightarrow\sqrt{x-1}=4\Leftrightarrow x-1=16\)

\(\Leftrightarrow x=17\)

Vậy, x=17

A: \(\Leftrightarrow5\sqrt{x-1}-\dfrac{15}{2}\cdot\dfrac{\sqrt{x-1}}{3}=6+\sqrt{x-1}\)

=>5/2*căn x-1-căn x-1=6

=>3/2*căn x-1=6

=>căn x-1=4

=>x-1=16

=>x=17

B:

a: ĐKXĐ: x>=0; x<>1

b: Sửa đề: \(A=\dfrac{\left(\sqrt{x}-1\right)^2}{\sqrt{x}-1}+\dfrac{x\sqrt{x}+1}{\sqrt{x}+1}\)

=căn x-1+x-căn x+1

=x

Bạn nên gõ đề bằng công thức toán (biểu tượng $\sum$ góc trái khung soạn thảo) để mọi người hiểu đề và hỗ trợ bạn tốt hơn nhé.