84/144 = 7/12                                225/60 = 15/4                                 169/65 = 13/5

                     64/48 = 4/3                                   96/42 = 16/7

( 7/12 - 15/4 - 13/5 ) : ( 3/2 - 4/3 - 16/7 )

= -173/30 : -89/42

= 1221/445

84/144 = 7/12;225/60 = 15/4;169/65 = 13/5;64/48 = 4/3;96/42 = 16/7

( 7/12 - 15/4 - 13/5 ) : ( 3/2 - 4/3 - 16/7 )

= -173/30 : -89/42

= 1221/445

18/7

TAI SAO LAI 18 / 7

18/7

\(\frac{1}{3}\)

16/24-1/3=2/3-1/3=1/3

16/24-1/3=2/3-1/3=1/3

Câu 1: \(\frac{17}{51}\)x \(\frac{45}{30}\)= \(\frac{1}{3}\)x \(\frac{3}{2}\)

                                   = \(\frac{1}{2}\).

Câu 2: \(\frac{24}{15}\)x \(\frac{56}{72}\)x \(\frac{10}{14}\)= \(\frac{8}{5}\)x \(\frac{7}{9}\)x \(\frac{5}{7}\)

                                                 = \(\frac{56}{45}\)x \(\frac{5}{7}\)

                                                 = \(\frac{8}{9}\)

Câu 3: \(\frac{32}{48}\times\frac{35}{21}\times\frac{63}{14}\times\frac{9}{30}=\frac{2}{3}\times\frac{5}{3}\times\frac{9}{2}\times\frac{3}{10}=\frac{3}{2}\)

k nha

a)17/51x45/40=1/3x3/2=3/6=1/2

b)24/15x56/72x10/14=8/5x7/9x5/7=8/9

c)32/48x35/21x63/14x9/30=2/3x5/3x9/2x3/10=3/2

x x 134 -x x24 -x x 10 = x x ( 134 - 24 - 10)

x = x x 100

x = 1300 : 100

x = 13

\(\frac{15}{25}=\frac{15:5}{25:5}=\frac{3}{5}\); \(\frac{6}{21}=\frac{6:3}{21:3}=\frac{2}{7}\)

\(\frac{3}{5}+\frac{2}{7}=\frac{31}{35}\)

\(\frac{15}{25}+\frac{6}{21}=\frac{3}{5}+\frac{2}{7}=\frac{21}{35}+\frac{10}{35}=\frac{31}{35}\)

15/25+6/21

ta có:

15/25=15:5/25:5=3/5

6/21=6:3/21:3=2/7

3/5+2/7=31/35

tick nha

hỏi chơi à?

4/5*5/24*1 và 1/7

miru

Rút gọn rồi tính: 

\(\frac{28}{35}.\frac{15}{72}.1\frac{7}{49}\)

\(=\frac{4}{5}.\frac{5}{24}.\frac{56}{49}\)

\(=\frac{4.5.8}{5.24.7}=\frac{4}{21}\)

\(\frac{28}{35}.\frac{15}{72}.1\frac{7}{49}\)

\(=\frac{4}{5}.\frac{5}{24}.\frac{7}{49}\)

\(=\frac{4}{21}\)

k mk nha, cảm ơn những người đã k

\(A=\sqrt{2}-\sqrt{x+2\sqrt{2x-4}}\)                 ( ĐKXĐ: \(x\ge2\))

\(\Rightarrow A\sqrt{2}=2-\sqrt{2x+4\sqrt{2x-4}}\)

                   \(=2-\sqrt{\left(\sqrt{2x-4}+2\right)^2}\)

                   \(=2-\sqrt{2x-4}-2\)

                    \(=-\sqrt{2x-4}\)  

\(\Rightarrow A=-\sqrt{\frac{2x-4}{2}}\)

           \(=-\sqrt{x-2}\)

\(A=-1\Leftrightarrow-\sqrt{x-2}=-1\)

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

                   \(\Leftrightarrow x=3\)( Thỏa mãn ĐKXĐ )

TK  NHA!