Tính \(\frac{9^{14}\times25^5\times8^7}{18^{12}\times625^{3\times}24^3}\)
Bài 1:
a, T = \(\frac{9^{14}\times25^6\times8^7}{18^{12}\times625^3\times24^3}\)
b, A = \(\frac{5\times4^{15}\times9^9-4\times3^{20}\times8^9}{5\times2^9\times6^{19}-7\times2^{29}\times27^6}\)
a) \(T=\frac{9^{14}\times25^6\times8^7}{18^{12}\times625^3\times24^3}\)
\(=\frac{\left(3^2\right)^{14}\times25^6\times\left(2^3\right)^7}{\left(2\times3^2\right)^{12}\times\left(25^2\right)^3\times\left(3\times2^3\right)^3}\)
\(=\frac{3^{28}\times25^6\times2^{21}}{2^{12}\times3^{24}\times25^6\times3^3\times2^9}\)
\(=\frac{3^{28}\times25^6\times2^{21}}{\left(2^{12}\times2^9\right)\times\left(3^{24}\times3^3\right)\times25^6}\)
\(=\frac{3^{28}\times25^6\times2^{21}}{2^{21}\times3^{27}\times25^6}=3\)
b) \(A=\frac{5\times4^{15}\times9^9-4\times3^{20}\times8^9}{5\times2^9\times6^{19}-7\times2^{29}\times27^6}\)
\(=\frac{5\times\left(2^2\right)^{15}\times\left(3^2\right)^9-2^2\times3^{20}\times\left(2^3\right)^9}{5\times2^9\times\left(2\times3\right)^{19}-7\times2^{29}\times\left(3^3\right)^6}\)
\(=\frac{5\times2^{30}\times3^{18}-2^2\times3^{20}\times2^{27}}{5\times2^9\times2^{19}\times3^{19}-7\times2^{29}\times3^{18}}\)
\(=\frac{5\times2^{30}\times3^{18}-2^{29}\times3^{20}}{5\times2^{28}\times3^{19}-7\times2^{29}\times3^{18}}\)
\(=\frac{2^{29}\times3^{18}\times\left(5\times2-3^2\right)}{2^{28}\times3^{18}\times\left(5\times3-7\times2\right)}\)
\(=\frac{2\times\left(10-9\right)}{15-14}=\frac{2\times1}{1}=2\)
1)Rút gọn:
a) \(\frac{9^{14}\times25^5\times8^7}{18^{12}\times625^3\times24^3}\)
b)\(\frac{71\times52+53}{530\times71-180}\)
2)CMR:
\(\frac{abab}{cdcd}=\frac{ababab}{cdcdcd}\)
3)Tính hợp lí:
\(A=\frac{1}{3}-\frac{3}{4}-\left(\frac{-3}{5}-\frac{1}{57}+\frac{1}{36}+\frac{-1}{15}\right)-\frac{2}{9}\)
1)
a) \(\frac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}=\frac{3^{28}.5^{10}.2^{21}}{2^{21}.3^{24}.5^{12}.3^3.2^9}=\frac{3}{5^2}=\frac{3}{25}\)
Bài 2:
\(\frac{abab}{cdcd}=\frac{ab.101}{cd.101}=\frac{ab}{cd};\frac{ababab}{cdcdcd}=\frac{ab.10101}{cd.10101}=\frac{ab}{cd}\)
Vậy \(\frac{ab}{cd}=\frac{abab}{cdcd}=\frac{ababab}{cdcdcd}\)
Rut gon phan so sau :
a)\(\frac{9^{14\times}25^5\times8^7}{18^{12}\times625^3\times24^3}\)
b)\(\frac{1\times3\times5\times...\times39}{21\times22\times23\times...\times40}\)
c)\(\frac{1\times3\times5\times...\times\left(2n-1\right)}{\left(n+1\right)\times\left(n+2\right)\times\left(n+3\right)\times...\times2n}\)
\(\frac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}=\frac{9^{12}.9^2.25^5.8^3.8^5}{9^{12}.2^{12}.25^6.8^3.3^3} =\frac{3^4.8^5 }{8^4.3^3}=3.8=24\)
a.\(\frac{7^3\times5^8}{49\times25^4}\)
b.\(\frac{3^9\times25\times5^3}{15\times625\times3^8}\)
c.\(\frac{2^{50}\times3^{61}+2^{90}\times3^{16}}{2^{51}\times3^{61}+2^{91}\times3^{16}}\)
d.\((\frac{2}{5}-\frac{1}{2})^2+(\frac{1}{2}+\frac{3}{5})^2\)
a) \(\frac{7^3.5^8}{49.25^4}=\frac{7^3.5^8}{7^2.5^8}=7\)
b) \(\frac{3^9.25.5^3}{15.625.3^8}=\frac{3^9.5^2.5^3}{3.5.5^4.3^8}=\frac{3^9.5^5}{3^9.5^5}=1\)
c) \(\frac{2^{50}.3^{61}+2^{90}.3^{16}}{2^{51}.3^{61}+2^{91}.3^{16}}=\frac{2^{50}.3^{16}\left(3^{45}+2^{40}\right)}{2^{51}.3^{16}\left(3^{45}+2^{40}\right)}=\frac{1}{2}\)
d) \(\left(\frac{2}{5}-\frac{1}{2}\right)^2+\left(\frac{1}{2}+\frac{3}{5}\right)^2\)
\(=\left(\frac{-1}{10}\right)^2+\left(\frac{11}{10}\right)^2\)
\(=\frac{1}{100}+\frac{121}{100}=\frac{122}{100}=\frac{61}{50}\)
a) \(\frac{7^3.5^8}{49.25^4}=\frac{7^3.5^8}{7^2.\left(5^2\right)^4}=\frac{7^3.5^8}{7^2.5^8}=7\)
b) \(\frac{3^9.25.5^3}{15.625.3^8}=\frac{3^9.5^2.5^3}{5.3.5^4.3^8}=\frac{3^9.5^5}{5^5.3^9}=1\)
c) \(\frac{2^{50}.3^{61}+2^{90}.3^{16}}{2^{51}.3^{61}+2^{91}.3^{16}}=\frac{2^{50}.3^{16}\left(3^{45}+2^{40}\right)}{2^{51}.3^{16}\left(3^{45}+2^{40}\right)}=\frac{1}{2}\)
d) \(\left(\frac{2}{5}-\frac{1}{2}\right)^2+\left(\frac{1}{2}+\frac{3}{5}\right)^2=\left(-\frac{1}{10}\right)^2+\left(\frac{11}{10}\right)^2=\frac{1}{100}+\frac{121}{100}=\frac{122}{100}=1,22\)
Tính :
a)\(\frac{0,8\times0,44\times1,25\times25}{10\times125\times4\times25\times8}\) b)\(\frac{13,5\times1420+4,5\times580\times3}{3+6+9+.....+24+27}\)
c)\((1,11+0,19-2.6):(2,06+0,54)-(\frac{1}{2}+\frac{1}{3}):2\)
d)\([2\frac{1}{3}+3,5]:[-4\frac{1}{6}+3\times\frac{1}{7}]+7,5\)
e)\(-15,5\times20,8+3,5\times9,2-15,5\times9,2+3.5\times20,8\)
Giúp mk với , thanks nhiều ạ
Tính hợp lí :
\(\frac{1}{7}.\frac{1}{3}+\frac{1}{7}.\frac{1}{2}-\frac{1}{7}\)
Rút gọn rồi tính :
1) \(\frac{5^4\times9^5}{15^3\times27^3}\)
2) \(\frac{8^8\times3^{14}}{9^6\times2^{20}}\)
3) \(\frac{4^{10}\times25^7}{5^{14}\times8^6}\)
4) \(\frac{25^7\times2^{15}}{8^5\times5^{12}}\)
Tính nhanh:\(\frac{1\times2\times3+2\times4\times6+3\times6\times9+4\times8\times12+5\times10\times15}{1\times3\times5+2\times6\times10+3\times9\times15+4\times12\times20+5\times15\times25}-\frac{1+2+3+2+4+6+3+6+9+4+8+12+5+10+15}{1+3+5+2+6+10+3+9+15+4+12+20+5+15+25}\)
Giúp mk vs, nhưng bài này hơi khó đấy, ai đúng mk tích ^_^
Bài 16: Tính nhanh
A =\(\frac{0,8\times0,4\times1,25\times25+0,6524+0,3476}{10\times125\times4\times25\times8}\)
B = \(\frac{18\times123+9\times4567\times2+3\times5310\times6}{1+4+7+10+...+55+58-410}\)
\(B=\frac{18\times123+9\times4567\times2+3\times5310\times6}{1+4+7+10+...+55+58-410}.\)
\(B=\frac{18\times123+9\times2\times4567+3\times6\times5310}{\left(1+4+7+10+....+55+58\right)-410}\)
\(B=\frac{18\times123+18\times4567+18\times5310}{\left(1+4+7+10+......+55+58\right)-410}\)
\(B=\frac{18\times\left(123+4567+5310\right)}{\left(1+4+7+10+....+55+58\right)-410}\)
\(B=\frac{18\times10000}{\left(1+4+7+10+....+55+58\right)-410}\)
Ta xét : 1 + 4 + 7 + 10 + .... + 55 + 58
Ta có : 4 - 1 = 3
7 - 4 = 3
10 - 4 = 3
................
58 - 55 = 3
Vậy khoảng cách giữa 2 số liền nhau trong dãy số trên hơn kém nhau 3 đơn vị
Dãy số trên có tất cả số số hạng là :
( 58 - 1 ) : 3 + 1 = 20 ( số )
tổng của dãy số trên là :
( 58 + 1 ) x 20 : 2 = 590
Thay vào ta có :
\(B=\frac{18\times10000}{590-410}\)
\(B=\frac{180000}{180}\)
\(B=1000\)
Mình nhầm nhé : ( Mình quên chưa chia 2 )
1 + 4 + 7 + 10 + ... + 58 - 410
= ( 58 + 1 ) x [ ( 50 - 1 ) : 3 + 1 ] : 2 - 410
= 59 x 20 : 2 - 410
= 590 - 410 = 180
=> B = 18 000 : 180 = 100
\(A=\frac{0,8\times0,4\times1,25\times25+0,6524+0,3476}{10\times125\times4\times25\times8}\)
\(A=\frac{0,8\times1,25\times0,4\times25+0,6524+0,3476}{10\times4\times25\times8\times125}\)
\(A=\frac{1\times10+1}{10\times100\times1000}\)
\(A=\frac{11}{1000000}\)
1. 1/30×29-1/29×28-1/28×27-...-1/3×2-1/2×1
2. 1/2×3+1/2×2+2/4×6+3/7×9+4/9×13+5/13×18+6/18×24
3. 8/6+14/12+22/20+32/30+44/42+58/56+74/72+92/90
1: \(=\dfrac{1}{29\cdot30}-\left(\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+...+\dfrac{1}{28\cdot29}\right)\)
\(=\dfrac{1}{29\cdot30}-\left(1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{28}-\dfrac{1}{29}\right)\)
\(=\dfrac{1}{29\cdot30}-\dfrac{28}{29}=\dfrac{1-28\cdot30}{870}=\dfrac{-859}{870}\)