\(1,4.\dfrac{15}{49}-[\dfrac{4}{5}+\dfrac{2}{3}]:2\dfrac{1}{5}\)
1,4 . \(\dfrac{15}{49}\) - (\(\dfrac{4}{5}\) + \(\dfrac{-2}{3}\)) : \(2\dfrac{1}{5}\)
\(=\dfrac{7}{5}\cdot\dfrac{15}{49}-\left(\dfrac{4}{5}-\dfrac{2}{3}\right):\dfrac{11}{5}\)
\(=\dfrac{3}{7}-\dfrac{2}{15}\cdot\dfrac{5}{11}\)
\(=\dfrac{3}{7}-\dfrac{2}{33}=\dfrac{99-14}{33\cdot7}=\dfrac{85}{231}\)
\(1,4\cdot\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
\(1,4\cdot\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\\ =\dfrac{7}{5}\cdot\dfrac{15}{49}-\dfrac{22}{15}:\dfrac{11}{5}\\ =\dfrac{3}{7}-\dfrac{22}{15}\cdot\dfrac{5}{11}=\dfrac{3}{7}-\dfrac{2}{3}=-\dfrac{5}{21}\)
1,4.15/49-(4/5+2/3): 2/1/5
= 7/5. 15/49 - 2/15: 11/5
= 3/7 - 2/33
= 85/231
Thực hiện phép tính:
\(\dfrac{1}{4}-\dfrac{2}{-3}-\dfrac{11}{8}\)
b) 1,4.\(\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
a) \(\dfrac{1}{4}-\dfrac{2}{-3}+\dfrac{11}{8}\\ =\dfrac{6+16-33}{24}=-\dfrac{11}{24}\)
b) \(1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\\ =\dfrac{7}{5}.\dfrac{15}{49}-\dfrac{22}{15}:\dfrac{11}{5}\\ =\dfrac{3}{7}-\dfrac{2}{3}\\ =\dfrac{9-14}{21}=-\dfrac{5}{21}\)
a, \(\dfrac{1}{4}-\dfrac{2}{-3}-\dfrac{11}{8}.\)
\(=\dfrac{1}{4}+\dfrac{2}{3}+\dfrac{-11}{8}.\)
\(=\dfrac{6}{24}+\dfrac{16}{24}+\dfrac{33}{24}.\)
\(=\dfrac{6+16+\left(-33\right)}{24}.\)
\(=\dfrac{-11}{24}.\)
b, \(1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}.\)
\(=\dfrac{7}{5}.\dfrac{15}{49}-\left(\dfrac{12}{15}+\dfrac{10}{15}\right):\dfrac{11}{5}.\)
\(=\dfrac{3}{7}-\dfrac{22}{15}:\dfrac{11}{5}.\)
\(=\dfrac{3}{7}-\dfrac{22}{15}.\dfrac{5}{11}.\)
\(=\dfrac{3}{7}-\dfrac{22.5}{15.11}.\)
\(=\dfrac{3}{7}-\dfrac{2.1}{3.1}.\)
\(=\dfrac{3}{7}-\dfrac{2}{3}.\)
\(=\dfrac{9}{21}-\dfrac{14}{21}.\)
\(=\dfrac{9-14}{21}=\dfrac{-5}{21}.\)
CHÚC BN HỌC TỐT!!! ^ - ^
Tìm giá trị của biểu thức :
\(A=-1,6:\left(1+\dfrac{2}{3}\right)\)
\(B=1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
\(A=-1,6:\left(1+\dfrac{2}{3}\right)\)
\(A=\dfrac{-16}{10}:\dfrac{5}{3}\)
\(A=\dfrac{-8}{5}.\dfrac{3}{5}\)
\(A=\dfrac{-24}{25}\)
\(B=1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
\(B=\dfrac{14}{10}.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):\dfrac{11}{5}\)
\(B=\dfrac{14}{10}.\dfrac{15}{49}-\dfrac{22}{15}:\dfrac{11}{5}\)
\(B=\dfrac{3}{7}-\dfrac{22}{15}:\dfrac{11}{5}\)
\(B=\dfrac{3}{7}-\dfrac{2}{3}\)
\(B=\dfrac{-5}{21}\)
\(A=-1,6:\left(1+\dfrac{2}{3}\right)\)
\(A=\dfrac{-8}{5}:\left(1+\dfrac{2}{3}\right)\)
\(A=\dfrac{-8}{5}:\dfrac{5}{3}\)
\(A=\dfrac{-24}{25}\)
\(B=1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
\(B=\dfrac{7}{5}.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):\dfrac{11}{5}\)
\(B=\dfrac{7}{5}.\dfrac{15}{49}-\dfrac{22}{15}:\dfrac{11}{5}\)
\(B=\dfrac{3}{7}-\dfrac{2}{3}\)
\(B=\dfrac{-5}{21}\)
\(A=-1,6:\left(1+\dfrac{2}{3}\right)\)
\(\Rightarrow A=\dfrac{-8}{5}:\left(1+\dfrac{2}{3}\right)\)
\(\Rightarrow A=\dfrac{-8}{5}:\left(\dfrac{3}{3}+\dfrac{2}{3}\right)\)
\(\Rightarrow A=\dfrac{-8}{5}:\dfrac{5}{3}\)
\(\Rightarrow A=\dfrac{-8}{5}.\dfrac{3}{5}\)
\(\Rightarrow A=\dfrac{-24}{25}\)
\(B=1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
\(\Rightarrow B=\dfrac{7}{5}.\dfrac{15}{49}-\left(\dfrac{12}{15}+\dfrac{10}{15}\right):\dfrac{11}{5}\)
\(\Rightarrow B=\dfrac{3}{7}-\dfrac{22}{15}.\dfrac{5}{11}\)
\(\Rightarrow B=\dfrac{3}{7}-\dfrac{2}{3}\)
\(\Rightarrow B=\dfrac{9}{21}-\dfrac{14}{21}\)
\(\Rightarrow B=\dfrac{9}{21}+\left(\dfrac{-14}{21}\right)\)
\(\Rightarrow B=\dfrac{-5}{21}\)
tính:
a) \(2\dfrac{3}{4}.\left(-0,4\right)-1\dfrac{3}{5}.2,75+\left(-1,2\right):\dfrac{4}{11}\)
b) \(1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
c) \(\left(-3,2\right).\dfrac{15}{64}+\left(0,8-2\dfrac{4}{15}\right):3\dfrac{2}{3}\)
d) \(0,02.\dfrac{-25}{2}+\dfrac{3}{8}+\left(-2\dfrac{9}{20}\right).\dfrac{2}{7}\)
e) \(34\%:\dfrac{51}{16}-3\dfrac{7}{9}.6,5-\left(0,4\right)^2\)
Cái này bn lầy máy tính ra tính tí là xong thôi
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) \(34\%:\dfrac{51}{16}-3\dfrac{7}{9}.6,5-\left(0,4\right)^2\)
= \(\dfrac{17}{50}.\dfrac{16}{51}-\dfrac{34}{9}.\dfrac{13}{2}-\dfrac{4}{25}\)
= \(\dfrac{8}{75}-\dfrac{221}{9}-\dfrac{4}{15}\)
= \(-\dfrac{5501}{225}\)
Thực hiện phép tính:
\(\dfrac{-5}{12}.\dfrac{2}{7}+\dfrac{7}{12}:\dfrac{-14}{3}\)
b) 1,4.\(\dfrac{15}{49}-\left(80\%+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
a, \(\dfrac{-5}{12}.\dfrac{2}{7}+\dfrac{7}{12}:\dfrac{-14}{3}\)
\(=\dfrac{-5}{42}+\dfrac{7}{12}:\dfrac{-14}{3}\)
\(=\dfrac{-5}{42}+\dfrac{-1}{8}\)
\(=\dfrac{-41}{168}\)
b, \(1,4.\dfrac{15}{49}-\left(80\%+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
\(=1,4.\dfrac{15}{49}-\dfrac{22}{15}:2\dfrac{1}{5}\)
\(=\dfrac{3}{7}-\dfrac{22}{15}:2\dfrac{1}{5}\)
\(=\dfrac{3}{7}-\dfrac{2}{3}\)
\(=\dfrac{-5}{21}\)
\(\dfrac{-5}{12}.\dfrac{2}{7}+\dfrac{7}{12}:\dfrac{-14}{3}=\dfrac{-5}{42}+\dfrac{-1}{8}\)
\(=\dfrac{-20}{168}+\dfrac{-8820}{168}=\dfrac{-8840}{168}=\dfrac{-1105}{21}\)
a, \(\dfrac{-5}{12}.\dfrac{2}{7}+\dfrac{7}{12}:\dfrac{-14}{3}\)
\(=\dfrac{-5}{42}+\dfrac{-1}{8}\)
\(=\dfrac{-41}{168}\)
b, \(1,4.\dfrac{15}{49}-\left(80\%+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
\(=\dfrac{7}{5}.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right).\dfrac{5}{11}\)
\(=\dfrac{3}{7}-\dfrac{22}{15}.\dfrac{5}{11}\)
\(=\dfrac{3}{7}-\dfrac{2}{3}\)
\(=\dfrac{-5}{21}\)
Bài 1: Rút gọn các phân số sau đến tối giản
a) \(\dfrac{3.21}{14.15}\) b) \(\dfrac{49+7.49}{49}\)
Bài 2: Thực hiện phép tính:
a) 8\(\dfrac{3}{4}\) - 5\(\dfrac{1}{4}\)
b) \(\dfrac{-3}{4}\) . \(\dfrac{4}{7}\) + \(\dfrac{-3}{5}\).\(\dfrac{3}{7}\)+\(\dfrac{2}{-5}\)
c) ( \(\dfrac{3}{4}+\dfrac{5}{6}+\dfrac{7}{12}\)). (-\(\dfrac{12}{7}\))
d) 1,4. \(\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
Bài 1 : Rút gọn các phân số sau đến tối giản :
a) \(\dfrac{3.21}{14.15}=\dfrac{3.3.7}{2.7.3.5}=\dfrac{1.3.1}{2.1.1.5}=\dfrac{3}{10}\)
b) \(\dfrac{49+49.7}{49}=\dfrac{49\left(1+7\right)}{49}=\dfrac{49.8}{49}=\dfrac{1.8}{1}=\dfrac{8}{1}=8\)
\(a,\dfrac{-8}{5}:\left(1+\dfrac{2}{3}\right)\) \(b,\dfrac{7}{5}x\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):\dfrac{11}{5}\)
\(c,\dfrac{1}{3}:\left(\dfrac{2}{9}-\dfrac{7}{8}\right)\) \(d,\left(\dfrac{1}{6}-\dfrac{4}{5}\right):\dfrac{7}{5}\)
Giúp mik nha:>>
A -\(\dfrac{24}{25}\)
B -\(\dfrac{5}{21}\)
C -\(\dfrac{24}{47}\)
D -\(\dfrac{19}{42}\)
tick cho mk
\(1\dfrac{13}{15}\) . 0,75 - (\(\dfrac{104}{195}+25\%\) ) . \(\dfrac{24}{47}\) . \(3\dfrac{12}{13}\) : 3 + 1,4 . \(\dfrac{15}{49}\) - ( \(80\%+\dfrac{2}{3}\) ) \(:2\dfrac{1}{5}\)