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A = 239
B = 556
C = -7.497
D = -8,8
E = 10
chán quá chưa được ai k
k tớ nhé
DÀI QUÁ ĐI
A=(27+53)+(46+34)+79
A=80+80+79
A=160+79
A=239
B = -377 - (98 - 277)
B=-377-98-277
B=[(-377)+277]-98
B=(-100)-98
B=-198
C= -1,7.2,3 + 1,7.(-3,7) - 1,7.3 - 0,17 : 0,1
C=1,7.(-2.3)+1,7.(-3,7)+1,7.(-3)+1,7
C=1,7.[(-2,3+(-3,7)+(-3)+1]
C=1,7.(-8)
C=-13,6
Còn mái câu kia mk hk pít lm pn th/cảm cho mk nhae
a) \(2\dfrac{3}{4}.\left(-0,4\right)-1\dfrac{3}{5}.2,75+\left(-1,2\right):\dfrac{4}{11}\)
= \(2,75.\left(-0,4\right)-\left(1,6\right).\left(2,75\right)+\left(-1,2\right).\dfrac{11}{4}\)
= \(2,75.\left(-0,4\right)-\left(1,6\right).\left(2,75\right)+\left(-1,2\right).\left(2,75\right)\)
= \(2,75.\left\{\left(-0,4\right)-\left(1,6\right)+\left(-1,2\right)\right\}\)
= \(2,75.\left(-3,2\right)\)
= \(-8,8\)
b) \(1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
= \(\dfrac{7}{5}.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):\dfrac{11}{5}\)
= \(\dfrac{7}{5}.\dfrac{15}{49}-\dfrac{22}{15}.\dfrac{5}{11}\)
= \(\dfrac{3}{7}-\dfrac{2}{3}\)
= \(-\dfrac{5}{21}\)
c) \(\left(-3,2\right).\dfrac{15}{64}+\left(0,8-2\dfrac{4}{15}\right):3\dfrac{2}{3}\)
= \(-\dfrac{16}{5}.\dfrac{15}{64}+\left(\dfrac{4}{5}-2\dfrac{4}{15}\right):\dfrac{11}{3}\)
= \(-\dfrac{16}{5}.\dfrac{15}{64}+\left(-\dfrac{22}{15}\right).\dfrac{3}{11}\)
= \(\left(-\dfrac{3}{4}\right)+\left(-\dfrac{2}{5}\right)\)
= \(-\dfrac{23}{20}\)
d) \(0,02.\dfrac{-25}{2}+\dfrac{3}{8}+\left(-2\dfrac{9}{20}\right).\dfrac{2}{7}\)
= \(\dfrac{1}{50}.\dfrac{-25}{2}+\dfrac{3}{8}+\left(-\dfrac{49}{20}\right).\dfrac{2}{7}\)
=\(\left(-\dfrac{1}{4}\right)+\dfrac{3}{8}+\left(-\dfrac{7}{10}\right)\)
= \(\dfrac{1}{8}+\left(-\dfrac{7}{10}=\right)\)
= \(-\dfrac{23}{40}\)
e) \(34\%:\dfrac{51}{16}-3\dfrac{7}{9}.6,5-\left(0,4\right)^2\)
= \(\dfrac{17}{50}.\dfrac{16}{51}-\dfrac{34}{9}.\dfrac{13}{2}-\dfrac{4}{25}\)
= \(\dfrac{8}{75}-\dfrac{221}{9}-\dfrac{4}{15}\)
= \(-\dfrac{5501}{225}\)
a) \(\dfrac{1}{15}+\dfrac{1}{35}+\dfrac{1}{63}+\dfrac{1}{99}+\dfrac{1}{143}+\dfrac{1}{195}\)
\(=\dfrac{1}{3.5}+\dfrac{1}{5.7}+\dfrac{1}{7.9}+\dfrac{1}{9.11}+\dfrac{1}{11.13}+\dfrac{1}{13.15}\)
\(=\dfrac{1}{2}\left(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-.....+\dfrac{1}{13}-\dfrac{1}{15}\right)\)
\(=\dfrac{1}{2}\left(\dfrac{1}{3}-\dfrac{1}{15}\right)\)
\(=\dfrac{1}{2}.\dfrac{4}{15}=\dfrac{2}{15}\)
b) \(\dfrac{4}{9}:\left(-\dfrac{1}{7}\right)+6\dfrac{5}{9}:\left(-\dfrac{1}{7}\right)\)
\(=\dfrac{4}{9}.\left(-7\right)+\dfrac{59}{9}\left(-7\right)\)
\(=-7\left(\dfrac{4}{9}+\dfrac{59}{9}\right)\)
\(=-7.7=-49\)
c) \(\left(3\dfrac{2}{5}-2\dfrac{2}{5}\right).\left(-\dfrac{5}{3}\right)+3.\left(2\dfrac{1}{2}:\dfrac{1}{2}\right)\)
\(=\left(\dfrac{17}{5}-\dfrac{12}{5}\right).\left(-\dfrac{5}{3}\right)+3.5\)
\(=-\dfrac{5}{3}+15=13\dfrac{1}{3}\)
d) \(1\dfrac{13}{5}.\left(0,5\right)^2.3+\left(\dfrac{8}{15}+1\dfrac{19}{60}\right):1\dfrac{23}{24}\)
\(=\dfrac{2}{7}+78\dfrac{8}{15}:\dfrac{47}{24}\)
( bạn tự tính nốt câu này nha ! )
C = (-1,7) . 2,3 + 1,7 . (-3,7) - 1,7 .3 - 0,17 : 0,1
=> C = -1,7 . 2,3 +( -1,7 ) . 3,7 - 1,7 . 3 - 1,7
=> C = -1,7 . ( 2,3 + 3,7 - 3 - 1 )
=> C = -1,7 . 2 = -3,4
a) \(\dfrac{-3}{7}+\dfrac{15}{26}-\left(\dfrac{2}{13}-\dfrac{3}{7}\right)\\ =\dfrac{-3}{7}+\dfrac{15}{26}-\dfrac{2}{13}+\dfrac{3}{7}\\ =\left(\dfrac{-3}{7}+\dfrac{3}{7}\right)+\left(\dfrac{15}{26}-\dfrac{2}{13}\right)\\ =0+\left(\dfrac{15}{26}-\dfrac{4}{26}\right)\\ =0+\dfrac{11}{26}\\ =\dfrac{11}{26}\)
\(c)\dfrac{-11}{23}.\dfrac{6}{7}+\dfrac{8}{7}.\dfrac{-11}{23}-\dfrac{1}{23}\\=\dfrac{-1}{23}\left ( \dfrac{66}{7}+\dfrac{88}{7}+1 \right )\\ =\dfrac{-1}{23}.23=-1\)
a) \(\dfrac{2}{3}x-\dfrac{3}{2}x=\dfrac{5}{12}\)
\(-\dfrac{5}{6}x=\dfrac{5}{12}\)
\(x=-\dfrac{1}{2}\)
b) \(\dfrac{2}{5}+\dfrac{3}{5}\cdot\left(3x-3.7\right)=-\dfrac{53}{10}\)
\(\dfrac{3}{5}\left(3x-3.7\right)=-\dfrac{57}{10}\)
\(3x-3.7=-\dfrac{19}{2}\)
\(3x=-5.8\)
\(x=-\dfrac{29}{15}\)
c) \(\dfrac{7}{9}:\left(2+\dfrac{3}{4}x\right)+\dfrac{5}{9}=\dfrac{23}{27}\)
\(\dfrac{7}{9}:\left(2+\dfrac{3}{4}x\right)=\dfrac{8}{27}\)
\(2+\dfrac{3}{4}x=\dfrac{21}{8}\)
\(\dfrac{3}{4}x=\dfrac{5}{8}\)
\(x=\dfrac{5}{6}\)
d) \(-\dfrac{2}{3}x+\dfrac{1}{5}=\dfrac{3}{10}\)
\(-\dfrac{2}{3}x=\dfrac{1}{10}\)
\(x=-\dfrac{3}{20}\)
5a)
\(A=27+46+79+34+53\\ =27+46+20+20+39+34+53\\ =\left(27+53+20\right)+\left(46+34+20\right)+39\\ =100+100+39\\ =200+39\\ =239\)
\(B=\left(-377\right)-\left(98-277\right)\\ =\left(-377\right)-98+277\\ =\left[\left(-377\right)+277\right]-98\\ =\left(-100\right)-98\\ =-198\)
\(C=\left(-1,7\right)\cdot2,3+1,7\cdot\left(-3,7\right)-1,7\cdot3-0,17:0,1\\ =\left(-1,7\right)\cdot2,3+1,7\cdot\left(-3,7\right)-1,7\cdot3-1,7\\ =\left(-1,7\right)\cdot\left(2,3+3,7+3+1\right)\\ =\left(-1,7\right)\cdot10\\ =-17\)
\(D=2\dfrac{3}{4}\cdot\left(-0,4\right)-1\dfrac{3}{5}\cdot2,75+\left(-1,2\right):\dfrac{4}{11}\\ =\dfrac{11}{4}\cdot\dfrac{-2}{5}-\dfrac{8}{5}\cdot\dfrac{11}{4}+\dfrac{-6}{5}:\dfrac{4}{11}\\ =\dfrac{11}{4}\cdot\dfrac{-2}{5}-\dfrac{8}{5}\cdot\dfrac{11}{4}+\dfrac{-6}{5}\cdot\dfrac{11}{4}\\ =\dfrac{11}{4}\cdot\left(\dfrac{-2}{5}-\dfrac{8}{5}+\dfrac{-6}{5}\right)\\ =\dfrac{11}{4}\cdot\dfrac{-16}{5}\\ =\dfrac{-44}{5}\)
\(E=\dfrac{\left(2^3\cdot5\cdot7\right)\cdot\left(5^2\cdot7^3\right)}{\left(2\cdot5\cdot7^2\right)^2}\\ =\dfrac{2^3\cdot5^3\cdot7^4}{2^2\cdot5^2\cdot7^4}\\ =2\cdot5\cdot1\\ =10\)
6a)
\(A=1\dfrac{13}{15}\cdot\left(0,5\right)^2\cdot3+\left(\dfrac{8}{15}-1\dfrac{19}{60}\right):1\dfrac{23}{24}\\ =\dfrac{28}{15}\cdot\left(0,5\right)^2\cdot3+\left(\dfrac{8}{15}-\dfrac{79}{60}\right):\dfrac{47}{24}\\ =\dfrac{28}{15}\cdot\left(0,5\right)^2\cdot3+\dfrac{-47}{60}:\dfrac{47}{24}\\ =\dfrac{28}{15}\cdot0,25\cdot3+\dfrac{-47}{60}\cdot\dfrac{24}{47}\\ =\dfrac{7}{15}\cdot3+\dfrac{-2}{5}\\ =\dfrac{7}{5}+\dfrac{-2}{5}\\ =\dfrac{5}{5}\\ =1\)
\(B=\dfrac{\left(\dfrac{11^2}{200}+0,415\right):0,01}{\dfrac{1}{12}-37,25+3\dfrac{1}{6}}\\ =\dfrac{\left(\dfrac{11^2}{200}+\dfrac{83}{200}\right):\dfrac{1}{100}}{\dfrac{1}{12}-\dfrac{149}{4}+\dfrac{19}{6}}\\ =\dfrac{\left(\dfrac{121}{200}+\dfrac{83}{200}\right)\cdot100}{\dfrac{1}{12}-\dfrac{447}{12}+\dfrac{38}{12}}\\ =\dfrac{\dfrac{102}{100}\cdot100}{\dfrac{-408}{12}}\\ =\dfrac{102}{-34}\\ =-3\)