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\(D=\left(-8\right).\left(\dfrac{3}{4}-\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)=\left(-8\right)\dfrac{1}{2}:\dfrac{13}{12}=\left(-4\right).\dfrac{12}{13}=-\dfrac{48}{13}\)
\(\text{A=}\left(\dfrac{7}{8}-0,25\right):\left(\dfrac{5}{6}-0,75\right)^2\)
\(A=\left(\dfrac{7}{8}-\dfrac{1}{4}\right):\left(\dfrac{5}{6}-\dfrac{3}{4}\right)^2\)
\(A=\left(\dfrac{7}{8}+\dfrac{-1}{4}\right):\dfrac{1}{144}\)
\(A=\dfrac{5}{8}.144=90\)
\(\text{B=}\dfrac{3}{4}.1\dfrac{4}{9}-\left(\dfrac{-3}{4}\right)\)
\(B=\dfrac{3}{4}.\dfrac{13}{9}+\dfrac{3}{4}\)
\(B=\dfrac{13}{12}+\dfrac{3}{4}\)
\(B=\dfrac{11}{6}\)
a: \(=\dfrac{9}{13}\cdot\dfrac{4}{5}=\dfrac{36}{65}\)
b: \(=\dfrac{-7}{10}:\dfrac{3}{2}=\dfrac{-7}{10}\cdot\dfrac{2}{3}=\dfrac{-14}{30}=-\dfrac{7}{15}\)
c: \(=\dfrac{7}{6}\left(3+\dfrac{1}{4}-\dfrac{1}{4}\right)=\dfrac{7}{6}\cdot3=\dfrac{7}{2}\)
Ta lần lượt có:
\(\dfrac{1}{0,25}=\dfrac{100}{25}=4;\) \(\left(1\dfrac{1}{4}\right)^2=\left(\dfrac{5}{4}\right)^2=\dfrac{25}{16};\)
\(\dfrac{1}{\left(\dfrac{4}{3}\right)^2}=\dfrac{1}{\dfrac{16}{9}}=\dfrac{9}{16};\) \(\left(\dfrac{5}{4}\right)^3=\dfrac{125}{64}\) và \(\dfrac{1}{\left(-\dfrac{2}{3}\right)^3}=\dfrac{1}{-\dfrac{8}{27}}=-\dfrac{27}{8}\)
Vậy \(P=4.\dfrac{25}{16}+25.\left[\dfrac{9}{16}:\dfrac{125}{64}\right]:\left(-\dfrac{27}{8}\right)\)
\(=\dfrac{25}{4}-25.\dfrac{9}{16}.\dfrac{64}{125}.\dfrac{8}{27}\)
\(=\dfrac{25}{4}-\dfrac{32}{15}\)
\(=\dfrac{375-128}{60}=\dfrac{247}{60}\)
P=4.(25/16)+25.(9/16:25/16):(-27/8)
=25/4 +25.(9/25):(-27/8)
=25/4 +9:(-27/8)
=25/4 +(-8/3)
=43/12
Bai 1: \(\left(-2\right)^3.\left(\dfrac{3}{4}-0,25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=\left(-8\right).\left(\dfrac{3}{4}-\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
\(=\left(-8\right).\dfrac{1}{2}:\left(\dfrac{27}{12}-\dfrac{14}{12}\right)\)
\(=\left(-4\right):\dfrac{13}{12}\)
\(=\left(-4\right).\dfrac{12}{13}\)
\(=\dfrac{-48}{13}\)
Bai 2:
\(a,4\dfrac{1}{3}:\dfrac{x}{4}=6:0,3\)
\(\dfrac{13}{3}:\dfrac{x}{4}=20\)
\(\dfrac{x}{4}=\dfrac{13}{3}:20\)
\(\dfrac{x}{4}=\dfrac{13}{60}\)
➩ \(x.60=4.13\) ➩ \(x.60=52\) ➩ \(x=\dfrac{13}{15}\)
Vay \(x=\dfrac{13}{15}\)
\(b,\left(2^3:4\right).2^{\left(x+1\right)}=64\)
\(\left(8:4\right).2^{x+1}=64\)
\(2.2^{x+1}=64\)
\(2^{x+1}=32\)
➩ \(2^{x+1}=2^5\) ➩ \(x+1=5\) ➩ \(x=4\)
Vay \(x=4\)
e)\(16\dfrac{2}{7}:\left(-\dfrac{3}{5}\right)+28\dfrac{2}{7}:\left(-\dfrac{3}{5}\right)\)
=\(\left(16\dfrac{2}{7}+28\dfrac{2}{7}\right):\left(-\dfrac{3}{5}\right)\)
=\(\dfrac{312}{7}\)\(:\left(-\dfrac{3}{5}\right)\)
=\(-\dfrac{516}{7}\)
a)\(\dfrac{7}{8}.\left(\dfrac{2}{12}+\dfrac{4}{10}\right)\)
=\(\dfrac{7}{8}.\left(\dfrac{1}{6}+\dfrac{2}{5}\right)\)
=\(\dfrac{7}{8}.\)\(\dfrac{17}{30}\)
=\(\dfrac{119}{240}\)
\(B=0,25+3,5-\left(\dfrac{1}{8}-\dfrac{2}{5}+1\dfrac{1}{4}\right)\)
\(=\dfrac{17}{20}-\left(\dfrac{39}{40}\right)\)
\(=\dfrac{-1}{8}\)
\(C=\dfrac{2}{3}-\left(\dfrac{-1}{4}\right)+\dfrac{3}{5}-\dfrac{7}{45}-\left(\dfrac{-5}{9}\right)+\dfrac{1}{12}+\dfrac{1}{35}\)
\(=\dfrac{2}{3}+\dfrac{1}{4}+\dfrac{3}{5}-\dfrac{7}{45}+\dfrac{5}{9}+\dfrac{1}{12}+\dfrac{1}{35}\)
\(=\dfrac{71}{35}\)
\(D=\left(5-\dfrac{3}{4}+\dfrac{1}{5}\right)-\left(6+\dfrac{7}{4}-\dfrac{8}{5}\right)-\left(2-\dfrac{5}{7}+\dfrac{16}{5}\right)\)
\(=5-\dfrac{3}{4}+\dfrac{1}{5}-6-\dfrac{7}{4}+\dfrac{8}{5}-2+\dfrac{5}{7}-\dfrac{16}{5}\)
\(=\left(5-6-2\right)+\left(\dfrac{-3}{4}-\dfrac{7}{4}\right)+\left(\dfrac{1}{5}+\dfrac{8}{5}-\dfrac{16}{5}\right)+\dfrac{5}{7}\)
\(=\left(-3\right)+\left(\dfrac{-5}{2}\right)+\left(\dfrac{-7}{5}\right)+\dfrac{5}{7}\)
\(=\dfrac{-433}{70}\)
\(=\dfrac{-11}{5}\cdot\dfrac{-9}{11}\cdot\dfrac{-5}{4}\cdot\dfrac{2}{5}+2\cdot\dfrac{1}{4}\)
\(=\dfrac{-1}{2}+\dfrac{1}{2}=0\)
\(=\left(\dfrac{1}{4}\cdot\dfrac{5}{4}\right)^{-1}\cdot\left(\dfrac{1}{4}\cdot\dfrac{4}{3}\right)^{-2}\cdot\left(\dfrac{2}{3}\right)^{-3}\)
\(=\left(\dfrac{5}{16}\right)^{-1}\cdot\left(\dfrac{1}{3}\right)^{-2}\cdot\left(\dfrac{2}{3}\right)^{-3}\)
\(=\dfrac{16}{5}\cdot9\cdot\dfrac{27}{8}=\dfrac{486}{5}\)
1)(-1/2)^2:1/4-2.(-1/2)^3+căn 4
=1/4:1/4-2.-1/8+2
= 1-(-1/4)+2
=1+1/4+2=13/4
2) 3-(-6/7)^0+căn 9 :2
= 3-1+3:2
=3-1+3/2=7/2
3) (-2)^3+1/2:1/8-căn 25 + |-64|
= -8+4-5+64= 55
4) (-1/2)^4+|-2/3|-2007^0
= 1/16+2/3-1
= -13/48
5) = 178/495:623/495-17/60:119/120
= 2/7-2/7=0
6) [2^3.(-1/2)^3+1/2]+[25/22+6/25-3/22+19/25+1/2]
= [-1+1/2]+[(25/22-3/22)+(6/25+19/25)+1/2]
= -1/2+[1+1+1/2]
= -1/2+5/2=2
Mấy cái dấu chấm đó là nhân nha bn!
\(\left(-2\right)^3.\left(\dfrac{3}{4}-0,25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=-8.\left(\dfrac{3}{4}-\dfrac{1}{4}\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=-8.\dfrac{3-1}{4}:\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=-8.\dfrac{2}{4}:\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=-8.\dfrac{1}{2}:\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=-4:\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=-4:\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
\(=-4:\left(\dfrac{27}{12}-\dfrac{14}{12}\right)\)
\(=-4:\dfrac{27-14}{12}\)
\(=-4:\dfrac{13}{12}\)
\(=-4.\dfrac{12}{13}\)
\(=\dfrac{-48}{13}\)