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a. \(\left(\frac{2}{3}\right)^3-\left(\frac{3}{4}\right)^2.\left(-1\right)^5=\frac{8}{27}-\frac{9}{16}.\left(-1\right)=\frac{8}{27}+\frac{9}{16}=\frac{371}{432}\)
b. \(12:\left(\frac{3}{4}-\frac{5}{6}\right)^2=12:\left(-\frac{1}{12}\right)^2=12:\frac{1}{144}=12.144=1728\)
c. \(\frac{7}{22}:\frac{3}{11}+\frac{7}{22}:\frac{4}{11}=\frac{7}{22}.\frac{11}{3}+\frac{7}{22}.\frac{11}{4}=\frac{7}{22}\left(\frac{11}{3}+\frac{11}{4}\right)\)
\(=\frac{7}{22}.\frac{77}{12}=\frac{49}{24}\)
d. \(\frac{12}{35}\left(\frac{7}{4}+\frac{13}{4}\right)-\frac{1}{3}=\frac{12}{35}.5-\frac{1}{3}=\frac{12}{7}-\frac{1}{3}=\frac{29}{21}\)
a) \(\left(-16\right).12=\left(-192\right)\)
b) \(22.\left(-5\right)=\left(-110\right)\)
c) \(\left(-2500\right).\left(-100\right)=\left(+250000\right)\)
d) \(\left(-11\right)^2=\left(-11\right).\left(-11\right)=\left(+121\right)\)
a, ( - 16 ) . 12 b, 22 . ( - 5 ) c, ( - 2500 ) . ( - 100 )
= - ( 16.12 ) = - ( 22 . 5 ) = 2500 . 100
= - 192 = - 110 = 250000
d, ( -11 )2 = [ ( -11 ) . ( -11 ) ]
= 121
1, Ta có :
a . 81 = 34 => 3x= 34 => x = 4 .
b. 125 = 53 => 5x+2 = 53 =>x + 2 = 3 => x = 1
c. 23 * 2x - 1 = 64
=> 23 + ( x - 1 ) = 64 = 26
=> 3 + ( x - 1 ) = 6
=> x - 1 = 6 - 3 = 3
x = 3 + 1
x = 4
(+27).(+5) = 135
(-27).(+5) = -135
(-27).(-5) = 135
(+5).(-27) = -135
a) (−4).(−5).(−6)= 20.(-6)= -120
b) (−3+6).(−4)= 3.(-4)= -12
c) (−3−5)(−3+5)= -8. 2 = -16
d) (−5−13):(−6)= -18:( -6)= 3
a) \(5\dfrac{4}{23}.27\dfrac{3}{47}+4\dfrac{3}{47}.\left(-5\dfrac{4}{23}\right)\)
\(=5\dfrac{4}{23}.27\dfrac{3}{47}+\left(-4\dfrac{3}{47}\right).5\dfrac{4}{23}\)
\(=5\dfrac{4}{23}.\left[27\dfrac{3}{47}+\left(-4\dfrac{3}{47}\right)\right]\)
\(=5\dfrac{4}{23}.\left(27\dfrac{3}{47}-4\dfrac{3}{27}\right)\)
\(=5\dfrac{4}{23}.23\)
\(=\dfrac{119}{23}.23\)
\(=\dfrac{119}{23}\)
b) \(4.\left(\dfrac{-1}{2}\right)^3+\dfrac{3}{2}\)
\(=4.\dfrac{-1}{6}+\dfrac{3}{2}\)
\(=\dfrac{-4}{6}+\dfrac{3}{2}\)
\(=\dfrac{-2}{3}+\dfrac{3}{2}\)
\(=\dfrac{-4}{6}+\dfrac{9}{6}\)
\(=\dfrac{5}{6}\)
c) \(\left(\dfrac{1999}{2011}-\dfrac{2011}{1999}\right)-\left(\dfrac{-12}{1999}-\dfrac{12}{2011}\right)\)
\(=\dfrac{1999}{2011}-\dfrac{2011}{1999}-\dfrac{-12}{1999}+\dfrac{12}{2011}\)
\(=\left(\dfrac{1999}{2011}+\dfrac{12}{2011}\right)-\left(\dfrac{2011}{1999}+\dfrac{-12}{1999}\right)\)
\(=\dfrac{2011}{2011}-\dfrac{1999}{1999}\)
\(=1-1\)
\(=0\)
d) \(\left(\dfrac{-5}{11}+\dfrac{7}{22}-\dfrac{-4}{33}-\dfrac{5}{44}\right):\left(\dfrac{381}{22}-39\dfrac{7}{22}\right)\)
(đợi đã, mình chưa tìm được hướng làm...)
a) |a| = 5 => a = 5 hay a = -5
b) |a| = 0 => a = 0
c) |a| = -3 không tìm được a nào như thế vì |a| không thể là số âm.
d) |a| = |-5| = 5 => a = 5 hay a = -5
e) -11|a| = -22 => |a| = (-22):(-11) = 2 => a = 2 hay a = -2
a) |a| = 5 => a = 5 hay a = -5
b) |a| = 0 => a = 0
c) |a| = -3 không tìm được a nào như thế vì |a| không thể là số âm.
d) |a| = |-5| = 5 => a = 5 hay a = -5
e) -11|a| = -22 => |a| = (-22):(-11) = 2 => a = 2 hay a = -2
Xét \(22.\left(-6\right)=\left(-132\right)\) :
\(\Rightarrow\left\{{}\begin{matrix}\left(+22\right).\left(+6\right)=\left(+132\right)\\\left(+6\right).\left(-22\right)=\left(-132\right)\\\left(-22\right).\left(+6\right)=\left(-132\right)\end{matrix}\right.\)
(+22).(+6) = 132
(-22).(-6) = 132
(-22).(+6) = -132
(+6).(-22) = -132