\(M=\frac{2.6.10+4.12.20+6.18.30+...+20.60.100}{1.2.3+2.4.6+3.6.9+...+10.20.30}\)

\(=\frac{2.6.10.\left(1+2+3+...+10\right)}{1.2.3.\left(1+2+3+...+10\right)}\)

\(=20\)

a. \(\frac{2x6x1}{33x24}=\frac{12}{792}=\frac{1}{66}\)

b. \(\frac{21x4}{9x7x5x3}=\frac{84}{945}=\frac{4}{45}\)
 

a. 2*6*1/33*24

bằng 12*1/33*24

bằng 1/33*2

bằng 1/66

b. 21*4/9*7*5*3

bằng 7*3*4/9*7*5*3

bằng 4/9*5

bằng 4/45.hk tốt

a) Ta có: \(\dfrac{25^{28}+25^{24}+25^{20}+...+25^4+1}{25^{30}+25^{28}+...+25^2+1}\)

\(=\dfrac{25^{24}\left(25^4+1\right)+25^{16}\left(25^4+1\right)+...+\left(25^4+1\right)}{25^{28}\left(25^2+1\right)+25^{24}\left(25^2+1\right)+...+\left(25^2+1\right)}\)

\(=\dfrac{\left(25^4+1\right)\left(25^{24}+25^{16}+25^8+1\right)}{\left(25^2+1\right)\left(25^{28}+25^{24}+...+1\right)}\)

\(=\dfrac{\left(25^4+1\right)\cdot\left[25^{16}\left(25^8+1\right)+\left(25^8+1\right)\right]}{\left(25^2+1\right)\left[25^{24}\left(25^4+1\right)+25^{16}\left(25^4+1\right)+25^8\left(25^4+1\right)+\left(25^4+1\right)\right]}\)

\(=\dfrac{\left(25^4+1\right)\left(25^8+1\right)\left(25^{16}+1\right)}{\left(25^2+1\right)\left(25^4+1\right)\left(25^{24}+25^{16}+25^8+1\right)}\)

\(=\dfrac{\left(25^8+1\right)\left(25^{16}+1\right)}{\left(25^2+1\right)\left[25^{16}\left(25^8+1\right)+\left(25^8+1\right)\right]}\)

\(=\dfrac{\left(25^8+1\right)\left(25^{16}+1\right)}{\left(25^2+1\right)\left(25^8+1\right)\left(25^{16}+1\right)}\)

\(=\dfrac{1}{25^2+1}=\dfrac{1}{626}\)

\(=\dfrac{x+5}{2x}+\dfrac{x-6}{x-5}-\dfrac{3x^2-2x-9}{2x\left(x-5\right)}\)

\(=\dfrac{\left(x+5\right)\left(x-5\right)+2x\left(x-6\right)-3x^2+2x+9}{2x\left(x-5\right)}\)

\(=\dfrac{x^2-25+2x^2-12x-3x^2+2x+9}{2x\left(x-5\right)}\)

\(=\dfrac{-10x-16}{2x\left(x-5\right)}=\dfrac{-5x-8}{x\left(x-5\right)}\)

\(\frac{1}{2}\sqrt{48}-2\sqrt{75}-\frac{\sqrt{33}}{\sqrt{11}}+5\sqrt{1\frac{1}{3}}\)

=\(\frac{1}{2}\sqrt{3.4^2}-2\sqrt{3.5^2}-\sqrt{\frac{33}{11}}+5\sqrt{\frac{4}{3}}\)

\(=2\sqrt{3}-10\sqrt{3}-\sqrt{3}+10\sqrt{\frac{1}{3}}\)

\(=2\sqrt{3}-10\sqrt{3}-\sqrt{3}+\frac{10}{3}\sqrt{3}\)

\(=\left(2-10-1+\frac{10}{3}\right)\sqrt{3}\)

\(=\frac{-17}{3}\sqrt{3}\)

\(\sqrt{150}+\sqrt{1,6}.\sqrt{60}+4,5\sqrt{2\frac{2}{3}}-\sqrt{6}\)

\(=\sqrt{6.5^2}+\sqrt{96}+4,5\sqrt{\frac{8}{3}}-\sqrt{6}\)

\(=5\sqrt{6}+\sqrt{6.4^2}+4,5\frac{\sqrt{24}}{3}-\sqrt{6}\)

\(=5\sqrt{6}+4\sqrt{6}+\frac{4,5.2\sqrt{6}}{3}-\sqrt{6}\)

\(=8\sqrt{6}+3\sqrt{6}\)

\(=11\sqrt{6}\)

Tự hòi tự trl :D ?

\(\frac{1}{2}\sqrt{48}-2\sqrt{75}-\frac{\sqrt{33}}{\sqrt{11}}+5\sqrt{1\frac{1}{3}}\)

\(=\frac{1}{2}\sqrt{16.3}-2.5\sqrt{3}-\sqrt{3}-\frac{10}{3}\sqrt{3}\)

\(=2\sqrt{3}-10\sqrt{3}-\sqrt{3}-\frac{10}{3}\sqrt{3}\)

\(=-9\sqrt{3}+\frac{10}{3}\sqrt{3}=\left(-9+\frac{10}{3}\right)\sqrt{3}\)

\(=-\frac{17}{3}\sqrt{3}\)

\(\sqrt{150}+\sqrt{1,6}.\sqrt{60}+4,5.\sqrt{2\frac{2}{3}}-\sqrt{6}\)

\(=\sqrt{25.6}+\sqrt{1,6.60}+4,8\sqrt{\frac{8}{3}}-\sqrt{6}\)

\(=5\sqrt{6}+\sqrt{16.6}+4,5.\frac{1}{3}\sqrt{3^2.\frac{4.2}{3}}-\sqrt{6}\)

\(=9\sqrt{6}+3\sqrt{6}-\sqrt{6}=11\sqrt{6}\)

Rút gọn phân số 1371/3656 ta được phân số tối giản là:

B.3/8

Nhớ k cho mình nha!

1.

a) \(\frac{16}{24}-\frac{1}{3}=\frac{16}{24}-\frac{8}{24}=\)\(\frac{8}{24}=\frac{1}{3}\)

b) \(\frac{4}{5}-\frac{12}{60}=\frac{48}{60}-\frac{12}{60}=\frac{36}{60}=\frac{9}{15}\)

3.

a)\(\frac{17}{6}-\frac{2}{6}=\frac{17-2}{6}=\frac{15}{6}\)

b) \(\frac{16}{15}-\frac{11}{15}=\frac{16-11}{15}=\frac{5}{15}=\frac{1}{3}\)

c) \(\frac{19}{12}-\frac{13}{12}=\frac{19-13}{12}=\frac{6}{12}=\frac{1}{2}\)

\(\frac{10}{25}=\frac{10:5}{25:5}=\frac{2}{5}\)

\(\frac{5}{20}=\frac{5:5}{20:5}=\frac{1}{4}\)

\(\frac{6}{30}=\frac{6:6}{30:6}=\frac{1}{5}\)

\(\frac{60}{20}=\frac{60:20}{20:20}=3\)

\(\frac{4}{12}=\frac{4:4}{12:4}=\frac{1}{3}\)

\(\frac{24}{30}=\frac{24:6}{30:6}=\frac{4}{5}\)

\(\frac{25}{100}=\frac{25:25}{100:25}=\frac{1}{4}\)

\(\frac{60}{80}=\frac{60:20}{80:20}=\frac{3}{4}\)

\(\frac{9}{18}=\frac{9:9}{18:9}=\frac{1}{2}\)

\(\frac{60}{36}=\frac{60:12}{36:12}=\frac{5}{3}\)

\(\frac{72}{54}=\frac{72:18}{54:18}=\frac{4}{3}\)

\(\frac{35}{210}=\frac{35:35}{210:35}=\frac{1}{6}\)

4/12=1/3

24/30=4/5

25/100=1/4

60/80=3/4

9/18=1/2

60/36=5/3

72/54=4/3

35/210=1/6

4/12 =1/3

24/30 =4/5

25/100 =1/4