Tính giá trị của biểu thức:
a) 75.84.13+75.2.42.54+75.21.4.33
b)148.32-22.2.16-26.4.8
c) 3mũ0+ 3mũ2+ 3mũ4+ 3mũ6+...+3mũ2002
d) 5+6+7+8+9+... +125
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\(a,=\dfrac{5}{6}+\dfrac{6}{7}\\ =\dfrac{35}{42}+\dfrac{36}{42}=\dfrac{71}{42}\\ b,=\dfrac{5}{6}+\dfrac{4}{9}\\ =\dfrac{15}{18}+\dfrac{8}{18}=\dfrac{23}{18}\)
|(5/8-5/14)+(3/8-9/14)|:4/7
=|(5/8+3/8)+(-5/14-9/14)|:4/7
=|1+(-1)|:4/7
=0
a) 32 . 53 + 92 = 9 . 125 + 81
= 1 125 + 81 = 1 206
b) 83 : 42 - 52 = 512 : 16 - 25 = 32 - 25 = 7
c) 33 . 92 - 52.9 + 18 : 6 = 27 . 81 - 25 . 9 + 3
= 2 187 - 225 + 3 = 1 962 + 3 = 1 965
a) 78 060 : (10 – 7) + 300 045
= 78 060 : 3 + 300 045
= 26 020 + 300 045
= 326 065
b) 26 000 + 9 015 × 6
= 26 000 + 54 090
= 80 090
a) Với a = 3,05 thì ta có:
\(a\times2,46\) \(=3,05\times2,46=7,503\)
b) Với \(a=\dfrac{15}{8}\) thì ta có:
\(\left(\dfrac{5}{6}+\dfrac{7}{12}\right):a\) \(=\left(\dfrac{5}{6}+\dfrac{7}{12}\right):\dfrac{15}{8}\) \(=\left(\dfrac{10}{12}+\dfrac{7}{12}\right)\times\dfrac{8}{15}\) \(=\dfrac{17}{12}\times\dfrac{8}{15}\) \(=\dfrac{34}{45}\)
a) Thay a=3,05 vào 2,46a, ta được:
\(2.46\cdot3.05=7.503\)
b) Thay \(a=\dfrac{15}{8}\) vào biểu thức \(\left(\dfrac{5}{6}+\dfrac{7}{12}\right):a\), ta được:
\(\left(\dfrac{5}{6}+\dfrac{7}{12}\right):\dfrac{15}{8}\)
\(=\dfrac{17}{12}\cdot\dfrac{8}{15}=\dfrac{34}{45}\)
a) \(\dfrac{9}{5}+\dfrac{9}{5}:\dfrac{9}{5}\)
\(=\dfrac{9}{5}+\dfrac{9}{5}\times\dfrac{5}{9}\)
\(=\dfrac{9}{5}+1\)
\(=\dfrac{14}{5}\)
b) \(\dfrac{7}{5}-\dfrac{1}{2}\times\dfrac{1}{3}\)
\(=\dfrac{7}{5}-\dfrac{1}{6}\)
\(=\dfrac{42}{30}-\dfrac{5}{30}\)
\(=\dfrac{37}{30}\)
\(a,\dfrac{9}{5}+\dfrac{9}{5}:\dfrac{9}{5}\)
\(=\dfrac{9}{5}+\dfrac{9}{5}\times\dfrac{5}{9}\)
\(=\dfrac{9}{5}+1\)
\(=\dfrac{9}{5}+\dfrac{5}{5}\)
\(=\dfrac{14}{5}\)
\(b,\dfrac{7}{5}-\dfrac{1}{2}\times\dfrac{1}{3}\)
\(=\dfrac{7}{5}-\dfrac{1}{6}\)
\(=\dfrac{42}{30}-\dfrac{5}{30}\)
\(=\dfrac{37}{30}\)
\(2\cdot\left|-21\right|-3\cdot\left|125\right|-5\cdot\left|-33\right|-\left|2\cdot21\right|\)
\(=2\cdot21-3\cdot125-5\cdot33-2\cdot21\)
\(=-3\cdot125-5\cdot33=-375-165=-540\)
a: \(=\left(2\sqrt{3}-12\sqrt{3}+15\sqrt{3}\right)\cdot\sqrt{3}=5\sqrt{3}\cdot\sqrt{3}=15\)
b: \(=\left(6\sqrt{2}-16\sqrt{2}+15\sqrt{2}\right):5=\sqrt{2}\)
c: \(=\dfrac{\left(2\sqrt{5}-6\sqrt{5}+15\sqrt{5}\right)}{\sqrt{5}}=17-6=11\)