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e) \(\frac{1}{7}.\frac{-3}{8}+\frac{-13}{8}.\frac{1}{7}\)
\(=\frac{1}{7}.\left[\left(-\frac{3}{8}\right)+\left(-\frac{13}{8}\right)\right]\)
\(=\frac{1}{7}.\left(-2\right)\)
\(=-\frac{2}{7}.\)
Chúc bạn học tốt!
a. = 1/20 + 5 - 1/2
= 101/20 - 1/2
= 91/20
b. = ( 6/15 - 3/5) - ( 7/8 + 2/16) + 3
= -1/5 - 1 + 3
= 9/5
c. = 15/7 . ( 3/5 - 8/5)
= 15/7 . ( -1)
= - 15/7
e. = -14/9 - 3/9
= -17/9
f. = 19/21 . ( 15/17 + 2/17) + 13/21
= 19/21 . 1 + 13/21
= 32/21
g. = 43/12 : 2 + 5/24
= 43/24 + 5/24
= 2
\(3\frac{1}{2}-\frac{1}{2}.\left(-4,25-\frac{3}{4}\right)^2:\frac{5}{4}\)
\(=\frac{7}{2}-\frac{1}{2}.\left(-4,25-0,75\right)^2:\frac{5}{4}\)
\(=\frac{7}{2}-\frac{1}{2}.\left(-5\right)^2:\frac{5}{4}\)
\(=\frac{7}{2}-\frac{1}{2}.5.\frac{4}{5}\)
\(=\frac{7}{2}-2\)
\(=\frac{7}{2}-\frac{4}{2}\)
\(=\frac{3}{2}\)
\(\frac{3}{7}.1\frac{1}{2}+\frac{3}{7}.0,5-\frac{3}{7}.9\)
\(=\frac{3}{7}.\left(\frac{3}{2}+\frac{1}{2}-9\right)\)
\(=\frac{3}{7}.\left(2-9\right)\)
\(=\frac{3}{7}.\left(-7\right)\)
\(=-3\)
\(\frac{125^{2016}.8^{2017}}{50^{2017}.20^{2018}}=\frac{\left(5^3\right)^{2016}.\left(2^3\right)^{2017}}{\left(5^2\right)^{2017}.2^{2017}.\left(2^2\right)^{2018}.5^{2018}}=\frac{\left(5^3\right)^{2016}.\left(2^3\right)^{2017}}{\left(5^3\right)^{2017}.\left(2^3\right)^{2017}.2.5}=\frac{1}{5^4.2}=\frac{1}{1250}\)( tính nhẩm, ko chắc đúng )
1
a) \(3\frac{1}{2}-\frac{1}{2}\cdot\left(-4,25-\frac{3}{4}\right)^2\) : \(\frac{5}{4}\)
= \(3\cdot25:\frac{5}{4}\)
= \(3\cdot\left(25:\frac{5}{4}\right)\)
=\(3\cdot20\)
=60
b)=\(\frac{3}{7}\cdot\left(1\frac{1}{2}+0,5-9\right)\)
=\(\frac{3}{7}\cdot\left(-7\right)\)
=\(-3\)
c) =
a) (-0,125)3 . (-8) = (-0,125). (-0,125)2 . (-8) = [(-0,125) . (-8)] . (-0,125)2 = 1.1/64 = 1/64
b) \(\frac{27^{15}}{9^{21}}=\frac{\left(3^3\right)^{15}}{\left(3^2\right)^{21}}=\frac{3^{45}}{3^{42}}=3^3=27\)
c) \(\left(-2,5\right)^3+\frac{2496^5}{\left(-832\right)^5}-\frac{98^{17}}{98^{16}}=-\frac{125}{8}+\left(-243\right)-98=-\frac{2853}{8}\)
d) \(\left(1-\frac{1}{3}-\frac{1}{6}\right)^2\cdot\left(16^{37}:2^{145}-1963^0\right)=\left(\frac{6}{6}-\frac{2}{6}-\frac{1}{6}\right)^2\left(16^{37}:2^{145}-1963^0\right)\)
\(\left(\frac{1}{2}\right)^2\cdot7=\frac{1}{4}\cdot7=\frac{7}{4}\)
a) \(\left(-0,125\right)^3.\left(-8\right)=\left(\frac{-1}{8}\right)^3.\left(-8\right)=\left(\frac{-1}{8}\right)^3\div\left(\frac{-1}{8}\right)=\left(\frac{-1}{8}\right)^2=\frac{1}{64}\)
b) \(27^{15}\div9^{21}=\left(3^3\right)^{15}\div\left(3^2\right)^{21}=3^{45}\div3^{42}=3^3=27\)
c) \(\left(-2,5\right)^3+2496^5\div\left(-832\right)^5-98^{17}\div98^{16}=\left(\frac{-5}{2}\right)^3-3^5-98\)
\(=\left(\frac{-125}{8}\right)-243-98=\frac{-2853}{8}\)
d) \(\left(1-\frac{1}{3}-\frac{1}{6}\right).\left(16^{37}\div2^{125}-1963^0\right)=\frac{1}{2}.\left[\left(2^4\right)^{37}\div2^{125}-1\right]\)
\(=\frac{1}{2}.\left[2^{148}\div2^{125}-1\right]=\frac{1}{2}.\left[2^{23}-1\right]=\frac{2^{23}-1}{2}\)