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\(=\dfrac{5\cdot2^{30}\cdot3^{18}-2^{29}\cdot3^{20}}{5\cdot2^{29}\cdot3^{19}-7\cdot2^{29}\cdot3^{18}}=\dfrac{2^{29}\cdot3^{18}\left(5\cdot2-3^2\right)}{2^{29}\cdot3^{18}\left(5\cdot3-7\right)}=\dfrac{10-9}{15-7}=\dfrac{1}{8}\)
a)= 2021.2021-2020.(2021+1)
= 2021.(2020+1)-2020.(2021+1)
= (2021.2020)+2021-(2020.2021)-2020
= 1
b) B= (1+2-3-4)+(5+6-7-8)+(9+10-11-12)...........+(2017+2018-2019-2020)+2021
B= -4+(-4)+....................(-4)+2021
B= -4x505+2021
B= -2020 + 2021
B = 1
Bạn cho mình hỏi là 5.4 vs mấy cái tương tự là 5 nhân 4 hay 5,4 vậy?
\(\dfrac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^9.6^{19}-7.2^{29}.27^6}=\dfrac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{5.2^9.2^{19}.3^{19}-7.2^{29}.3^{18}}=\dfrac{2^{29}.3^{18}\left(5.2-3^2\right)}{2^{28}.3^{18}\left(5.3-7.2\right)}=\dfrac{2^{29}.3^{18}}{2^{28}.3^{18}}=\dfrac{2^{29}}{2^{28}}=2^1=2\)
Sửa đề:\(\dfrac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^9\cdot6^{19}-7\cdot2^{29}\cdot27^6}\)
\(=\dfrac{5\cdot2^{30}\cdot3^{18}-3^{20}\cdot2^{29}}{5\cdot2^9\cdot3^{19}\cdot2^{19}-7\cdot2^{29}\cdot3^{18}}\)
\(=\dfrac{3^{18}\cdot2^{29}\cdot\left(5\cdot2-9\right)}{2^{28}\cdot3^{18}\cdot\left(5\cdot3-7\cdot2\right)}=2\)
a: \(A=21\cdot100-11\cdot100+90\cdot100+100\cdot125\cdot16\)
\(=100\left(21-11+90\right)+100\cdot2000\)
\(=100\left(10+90+2000\right)=2100\cdot100=210000\)
b: \(=\dfrac{5\cdot2^{30}\cdot3^{18}-2^{29}\cdot3^{20}}{5\cdot2^{28}\cdot3^{19}-7\cdot2^{29}\cdot3^{18}}\)
\(=\dfrac{2^{29}\cdot3^{18}\left(5\cdot2-3^2\right)}{2^{28}\cdot3^{18}\left(5\cdot3-7\cdot2\right)}=2\)
\(A=\dfrac{5.4^{15}.9^9-4.3^{20}.8^9}{7.2^{29}.27^6-5.2^9.6^{19}}\)
\(A=\dfrac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{7.2^{29}.3^{18}-5.2^9.2^{19}.3^{19}}\)
\(A=\dfrac{2^{29}.3^{18}.\left(5.2-3^2\right)}{2^{28}.3^{18}.\left(7.2-5.3\right)}\)
\(A=\dfrac{2.\left(10-9\right)}{14-15}=\dfrac{2}{-1}=-2\)
Chúc bạn học tốt!!!
\(A=\dfrac{5.4^{15}.9^9-4.3^{20}.8^9}{7.2^{29}.27^6-5.2^9.6^{19}}=\dfrac{5.\left(2^2\right)^{15}.\left(3^2\right)^9-2^2.3^{20}.\left(2^2\right)^9}{7.2^{29}.27^6-5.2^9.\left(2.3\right)^{19}}\)
\(=\dfrac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{7.2^{29}.3^{18}-5.2^9.2^{19}.3^{19}}\)
\(=\dfrac{2^{29}.3^{18}\left(5.2-3^2\right)}{2^{28}.3^{18}\left(7.2-5.3\right)}\)
\(=\dfrac{2\left(10-9\right)}{14-15}=\dfrac{2}{-1}=-2\)
\(\dfrac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^9.6^{19}-7.2^{29}.27^6}\)
\(=\dfrac{5.\left(2^2\right)^{15}.\left(3^2\right)^9-2^2.3^{20}.\left(2^3\right)^9}{5.2^2.\left(3.2\right)^{19}-7.2^{29}.\left(3^3\right)^6}\)
\(=\dfrac{5.2^{30}.3^{18}-2^2.2^{27}.3^{20}}{5.2^2.2^{19}.3^{19}-7.2^{29}.3^{18}}\)
\(=\dfrac{5.2^{30}.3^{18}-2^{29}.3^{20}}{5.2^{28}.3^{19}-7.2^{29}.3^{18}}\)
\(=\dfrac{2^{29}.3^{18}.\left(5.2-3\right)}{2^{28}.3^{18}.\left(5.1.3-7.2.1\right)}\)
\(=\dfrac{2^{29}.3^{18}.1}{2^{28}.3^{18}.1}\)
\(=\dfrac{2^{29}}{2^{28}}\)
\(=2\)
\(=>M=\dfrac{2^{28}.3^{18}.5-2^{29}.3^{20}}{2^{28}.3^{19}.5-2^{29}.3^{18}.7}\)
\(=\dfrac{2^{28}.3^{18}\left(5-2.3^2\right)}{2^{28}.3^{18}\left(3.5-2.7\right)}\)
\(=5-2.3^2\)
\(=5-2.9\)
\(=5-18\)
\(=-13\)
\(#Nzgoca\)