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a: 27^4=(3^3)^4=3^12<3^18
b: 49^4=(7^2)^4=7^8
c: 9^16=(9^2)^8=81^8>27^8
\(c)\) \(C=\frac{\frac{2}{7}+\frac{2}{5}+\frac{2}{17}-\frac{2}{293}}{\frac{3}{7}+\frac{3}{5}+\frac{3}{17}-\frac{3}{293}}\)
\(C=\frac{2\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}-\frac{1}{293}\right)}{3\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}-\frac{1}{193}\right)}\)
\(C=\frac{2}{3}\)
Bạn Cô nàng Thiên Bình làm đúng hết òi =.=
a=7.[1/8+1/27-1/49]
------------------------
11.[1/8+1/27-1/49]
=7/11
cau b,c tuong tu nha h mk
\(\frac{\left(\frac{5}{8}+\frac{5}{27}-\frac{5}{49}\right)\cdot8\cdot27\cdot49}{\left(\frac{11}{8}+\frac{11}{27}-\frac{11}{49}\right)\cdot8\cdot27\cdot49}+\frac{6}{11}\)
\(=\frac{8+27-49}{8+27-49}+\frac{6}{11}\)
\(=1+\frac{6}{11}\)
\(=\frac{11}{11}+\frac{6}{11}=\frac{17}{11}\)
\(\frac{\frac{5}{8}+\frac{5}{27}-\frac{5}{49}}{\frac{11}{8}+\frac{11}{27}-\frac{11}{49}}+\frac{6}{11}\)
\(=\frac{5\left(\frac{1}{8}+\frac{1}{27}-\frac{1}{49}\right)}{11\left(\frac{1}{8}+\frac{1}{27}-\frac{1}{49}\right)}+\frac{6}{11}\)
\(=\frac{5}{11}+\frac{6}{11}=\frac{11}{11}=1\)
Ta có: \(\left(-\dfrac{3}{2}\right)^3+\dfrac{-49}{24}\cdot\dfrac{3}{14}-\left(\dfrac{5}{8}-\dfrac{27}{8}\right)\)
\(=\dfrac{-27}{8}+\dfrac{-7}{2}\cdot\dfrac{1}{8}-\dfrac{-22}{8}\)
\(=\dfrac{-27+22}{8}+\dfrac{-7}{16}\)
\(=\dfrac{-5}{8}+\dfrac{-7}{16}\)
\(=\dfrac{-10}{16}+\dfrac{-7}{16}\)
\(=\dfrac{-17}{16}\)
13)\(\dfrac{45}{8}\left(\dfrac{4}{15}-\dfrac{7}{8}\right)+\dfrac{45}{8}\left(\dfrac{11}{15}+\dfrac{9}{8}\right)\)
=\(\dfrac{45}{8}\left(\dfrac{4}{15}-\dfrac{7}{8}+\dfrac{11}{15}+\dfrac{9}{8}\right)\)
=\(\dfrac{45}{8}\left[\left(\dfrac{4}{15}+\dfrac{11}{15}\right)-\left(\dfrac{7}{8}-\dfrac{9}{8}\right)\right]\)
=\(\dfrac{45}{8}.\dfrac{5}{4}\)=\(\dfrac{225}{32}\)
14)\(\dfrac{15}{7}\left(\dfrac{49}{35}-\dfrac{27}{8}\right)-\left(\dfrac{2}{5}-\dfrac{27}{4}\right):\dfrac{7}{15}\)
=\(\dfrac{15}{7}\left(\dfrac{49}{35}-\dfrac{27}{8}\right)-\left(\dfrac{2}{5}-\dfrac{27}{4}\right).\dfrac{15}{7}\)
=\(\dfrac{15}{7}\left[\left(\dfrac{49}{35}-\dfrac{27}{8}\right)-\left(\dfrac{2}{5}-\dfrac{27}{4}\right)\right]\)
=\(\dfrac{15}{7}\left(\dfrac{49}{35}-\dfrac{27}{8}-\dfrac{2}{5}+\dfrac{27}{4}\right)\)
=\(\dfrac{15}{7}.\dfrac{35}{8}\)=\(\dfrac{75}{8}\)
a: =-2/49-5/3+2/49=-5/3
b: \(=\dfrac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^9\cdot6^{19}-7\cdot2^{29}\cdot27^6}\)
\(=\dfrac{5\cdot2^{30}\cdot3^{18}-3^{20}\cdot2^{27}\cdot2^2}{5\cdot2^9\cdot2^{19}\cdot3^{19}-7\cdot2^{29}\cdot3^{18}}\)
\(=\dfrac{5\cdot2^{30}\cdot3^{18}-3^{20}\cdot2^{29}}{5\cdot2^{28}\cdot3^{19}-7\cdot2^{29}\cdot3^{18}}\)
\(=\dfrac{2^{29}\cdot3^{18}\left(2\cdot3-3^2\right)}{2^{28}\cdot3^{18}\left(5\cdot3-7\cdot2\right)}=2\cdot\dfrac{6-9}{15-14}=2\cdot\left(-3\right)=-6\)
a) (68 - 8) . 14 + (-27 - 33) . 15
=60.14+(-60).15
=-60.(15-14)
=-60.1
=-60
b) 37 . (55 - 49) - 49 . (55 - 37)
=37.55-37.49-49.55-49.37
=37.55-49.55
=55(37-49)
=55.(-12)
=-660
c) (-4) . 19 . (-8) . (-25) . (125)
=[-4.(-25)].[-8.(-125)].19
=100.1000.19
=1900000
d) 32 . (-125) . 17 . (-25)
=(32.17).[-125.(-25)]
=544.3125
=1700000
2115 = 315 x 715 (1)
275 x 498 = (33)5 x (72)8 = 315x716. (2)
Từ (1) và (2) suy ra 2115 < 275 x 498
2115 = 315 x 715 (1)
275 x 498 = (33)5 x (72)8 = 315x716. (2)
Từ (1) và (2) suy ra 2115 < 275 x 498
\(\dfrac{8}{27}-\dfrac{49}{4}+\left(-\dfrac{8}{27}\right)\)
\(=\left[\dfrac{8}{27}+\left(-\dfrac{8}{27}\right)\right]-\dfrac{49}{4}\)
\(=0-\dfrac{49}{4}\)
\(=-\dfrac{49}{4}\)
#Toru
\(\dfrac{8}{27}-\dfrac{49}{4}+\left(-\dfrac{8}{27}\right)\\ =\left(-\dfrac{8}{27}+\dfrac{8}{27}\right)-\dfrac{49}{4}\\ =0-\dfrac{49}{4}\\ =-\dfrac{49}{4}\)