(=) (x+3)^2. (x-3)^2.(x-3).(x+3)

(=) (x+3)^3 . (x-3)^3 

dấu . là dấu  nhân nhé bn 

Trả lời :

\(\frac{9}{5}\times\frac{25}{77}\times\frac{7}{9}=\)\(\frac{45}{77}\times\frac{7}{9}=\)\(\frac{5}{11}\)

# Hok tốt !

\(\frac{9}{5}\times\frac{25}{77}\times\frac{7}{9}\)

\(=\frac{9\times25\times7}{5\times77\times9}\)

\(=\frac{9\times5\times5\times7}{5\times11\times7\times9}\)

\(=\frac{5}{11}\)

(Ở dòng thứ 3, những số nào giống nhau thì bn gạch đi nha, vì ở máy tính mk ko gạch đc)

\(\frac{9}{5}.\frac{25}{77}.\frac{7}{9}=\left(\frac{9}{5}.\frac{7}{9}\right).\frac{25}{77}=\frac{7}{5}.\frac{25}{77}=\frac{25}{55}=\frac{5}{11}\)

~HT~

a) Ta có: \(\dfrac{7\cdot25}{14\cdot10}\)

\(=\dfrac{7\cdot5\cdot5}{7\cdot2\cdot2\cdot5}\)

\(=\dfrac{5}{4}\)

b) Ta có: \(\dfrac{24\cdot15-14\cdot9}{36\cdot12}\)

\(=\dfrac{9\cdot8\cdot5-14\cdot9}{36\cdot12}\)

\(=\dfrac{9\cdot\left(8\cdot5-14\right)}{9\cdot4\cdot12}\)

\(=\dfrac{40-14}{4\cdot12}\)

\(=\dfrac{13}{24}\)

a) \(\dfrac{7.25}{14.10}\)

= \(\dfrac{7.5.5}{7.2.5.2}\)

= \(\dfrac{5}{4}\)

c) \(\dfrac{1^3.3^2}{6^3.5}\)

= \(\dfrac{3^2}{\left(2.3\right)^3.5}\)

= \(\dfrac{1}{2^3.3.5}\)

= \(\dfrac{1}{120}\)

tông so phan bang nhau la 9+11=20( phần)

tử của phân số đó là

4120 :20.1854

mẫu của phân số đó là

4120-1854=2266

vậy phân số cần tìm là

1854/2266

nhớ k cho mik nhá

k cho mik nhá bn

Tử số là :

    4120 : ( 9 + 11 ) x 9 = 1854

Mẫu số là : 

  4120 - 1854 = 2266

\(\Rightarrow\frac{1854}{2266}\)

Bài 1: 

\(\dfrac{x^2-3}{x+\sqrt{3}}=\dfrac{\left(x+\sqrt{3}\right)\left(x-\sqrt{3}\right)}{x+\sqrt{3}}=x-\sqrt{3}\)

Bài 2: 

a) Ta có: \(A=\sqrt{16x+16}-\sqrt{9x+9}+\sqrt{4x+4}+\sqrt{x+1}\)

\(=4\sqrt{x+1}-3\sqrt{x+1}+2\sqrt{x+1}+\sqrt{x+1}\)

\(=4\sqrt{x+1}\)

b) Để A=16 thì \(\sqrt{x+1}=4\)

\(\Leftrightarrow x+1=16\)

hay x=15

Viết latex cho dễ hiểu bn ơi

\(A=\left(\frac{21}{x^2-9}-\frac{x-4}{3-x}-\frac{x-1}{3+x}\right)\div\left(1-\frac{1}{x+3}\right)\)

\(=\left(\frac{21}{\left(x-3\right)\left(x+3\right)}+\frac{\left(x-4\right)\left(x+3\right)}{\left(x-3\right)\left(x+3\right)}-\frac{\left(x-1\right)\left(x-3\right)}{\left(x-3\right)\left(x+3\right)}\right)\div\left(\frac{x+3}{x+3}-\frac{1}{x+3}\right)\)

\(=\left(\frac{21}{\left(x-3\right)\left(x+3\right)}+\frac{x^2-x-12}{\left(x-3\right)\left(x+3\right)}-\frac{x^2-4x+3}{\left(x-3\right)\left(x+3\right)}\right)\div\frac{x+2}{x+3}\)

\(=\frac{21+x^2-x-12-x^2+4x-3}{\left(x-3\right)\left(x+3\right)}\times\frac{x+3}{x+2}\)

\(=\frac{3x+6}{x-3}\times\frac{1}{x+2}=\frac{3\left(x+2\right)}{\left(x-3\right)\left(x+2\right)}=\frac{3}{x-3}\)

\(A=\left(\frac{21}{x^2-9}-\frac{x-4}{3-x}-\frac{x-1}{3+x}\right):\left(1-\frac{1}{x+3}\right)\)

\(=\left(\frac{21}{x^2-9}+\frac{x-4}{x-3}-\frac{x-1}{x+3}\right):\left(\frac{x+2}{x+3}\right)\)

\(=\left(\frac{21}{\left(x-3\right)\left(x+3\right)}+\frac{\left(x-4\right)\left(x+3\right)}{\left(x-3\right)\left(x+3\right)}-\frac{\left(x-1\right)\left(x-3\right)}{\left(x-3\right)\left(x+3\right)}\right):\left(\frac{x+2}{x+3}\right)\)

\(=\left(\frac{21+x^2-x-12-x^2+4x-3}{\left(x-3\right)\left(x+3\right)}\right):\left(\frac{x+2}{x+3}\right)\)

\(=\frac{6+3x}{\left(x-3\right)\left(x+3\right)}.\frac{x+3}{x+2}=\frac{3\left(x+2\right)\left(x+3\right)}{\left(x-3\right)\left(x+3\right)\left(x+2\right)}=\frac{3}{x-3}\)

Ta có: \(T=\sqrt{x^2-6x+9}+\sqrt{x^2+6x+9}\)

\(=\left|x-3\right|+\left|x+3\right|\)

\(=3-x+x+3\)

\(=6\)