1) A= \(\dfrac{5.2^3+40.7}{40.2^3}\)
tính (nhanh nếu có thể)
a)\(5.2^4+2.3^3-3,4\)
b)\(\dfrac{\dfrac{1}{3}-0,25+0,2}{1\dfrac{1}{6}-0,875+0,7}\)
a) \(5.2^4+2.3^3-3,4\)
\(=5.2.2^3+2.3^3-3,4\)
\(=2.40+2.27-3,4\)
\(=2\left(40+37\right)-3,4\)
\(=2.77-4,3\)
\(=154-4,3=149,7\)
b) \(\dfrac{\dfrac{1}{3}-0,25+0,2}{1\dfrac{1}{6}-0,875+0,7}=\dfrac{2\left(\dfrac{1}{6}-0,125+\dfrac{1}{10}\right)}{7\left(\dfrac{1}{6}-0,125+\dfrac{1}{10}\right)}=\dfrac{2}{7}\)
a. \(5.2^4+2.3^3-3,4\)
\(=5.2^3.2+2.27-3,4\)
\(=2.\left(40+27\right)-3,4\)
\(=2.67-3,4\)
= 134 - 3,4 = 130,6
Tính bằng cách thuận tiện nhất:
A) (40.7-17.5):0.25
B) 3/4 giờx10+45 phút x10
ta có: A:0.25=A x 4
Ta có
A)(40.7-17.5)x4
=23.2x4=92.8
B)ko biết:)))))))))))))))))))))))))))
Câu 1: Rút gọn các biểu thức sau:
C = \(\dfrac{8^2.9^5}{3^9.4^3}\)
D = \(\dfrac{81^6.9^5}{27^7.3^{11}}\)
F = \(\dfrac{8^{15}.25^7}{125^5.2^{47}}\)
G = \(\dfrac{10^2.5^3}{8.25^2}\)
\(C=\dfrac{2^6\cdot3^{10}}{3^9\cdot2^6}=3\\ D=\dfrac{3^{24}\cdot3^{10}}{3^{21}\cdot3^{11}}=\dfrac{3^{34}}{3^{32}}=3^2=9\\ F=\dfrac{2^{45}\cdot5^{14}}{5^{15}\cdot2^{47}}=\dfrac{1}{2^2\cdot5}=\dfrac{1}{20}\\ G=\dfrac{2^2\cdot5^2\cdot5^3}{2^3\cdot5^4}=\dfrac{1\cdot5}{2}=\dfrac{5}{2}\)
C=3
D=9
F=1/20
G=5/2
Em ko giải chi tiết vì nó lâu
Mong thông cảm!
C= \(\dfrac{8^2.9^5}{3^9.4^3}\)
= \(\dfrac{\left(2^3\right)^2.\left(3^2\right)^5}{3^9.\left(2^2\right)^3}\)
= \(\dfrac{2^6.3^{10}}{3^9.2^6}\)
= \(\dfrac{3^1}{1}\)
= \(\dfrac{3}{1}\)
Tìm x , y:
a , \(\dfrac{2}{3}.3^{x+1}-7.3^x=405\)
b , \(\left(0,4x-1,3\right)^2=5,29\)
c , \(5.2^{x+1}.2^{-2}-2^x=384\)
d , \(4^x+4^{x+3}=4160\)
e , \(2^{x-1}+5.2^{x-2}=\dfrac{7}{32}\)
a: \(\Leftrightarrow3^x\cdot\left(\dfrac{2}{3}\cdot3-7\right)=405\)
\(\Leftrightarrow3^x=-81\)(vô lý)
b: \(\left(0,4x-1,3\right)^2=5,29\)
=>0,4x-1,3=2,3 hoặc 0,4x-1,3=-2,3
=>0,4x=3,6 hoặc 0,4x=-1
=>x=9 hoặc x=-2,5
c: \(5\cdot2^{x+1}\cdot2^{-2}-2^x=284\)
\(\Leftrightarrow2^x\cdot5\cdot2\cdot2^{-2}-2^x=284\)
\(\Leftrightarrow2^x\cdot\left(\dfrac{5}{2}-1\right)=284\)
\(\Leftrightarrow2^x=\dfrac{568}{3}\)(vô lý)
d: \(\Leftrightarrow4^x\left(1+4^3\right)=4160\)
\(\Leftrightarrow4^x=64\)
hay x=3
Giúp mình với ạ ! Cảm ơn
Bài 1: Tính
a)700:{100-[40.2-(20.5):5]}
b)95:[100-15.4 mũ 2.(3-.5]}
\(a,700:\left\{100-\left[40.2-\left(20.5\right):5\right]\right\}\\ =700:\left\{100-\left[80-20\right]\right\}\\ =700:40\\ =\dfrac{35}{2}.\)
Kiểm tra lại dấu phần \(b,\) .
700:{100-[40.2-100:5]}
700:(100-80-20)
700:0
70
a. 700 : { 100 - [ 40 . 2 - ( 20 . 5 ) : 5 ] }
= 700: { 100 - [ 40 . 2 - 100 : 5 ] }
= 700 : { 100 - [ 80-20 ] }
= 700 : { 100 - 60 }
= 700 : 40
= 17.5
Tính : \(\dfrac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{5.2^9.2^{19}.3^{19}-7.2^{29}.3^{18}}\)
\(=\dfrac{5\cdot2^{30}\cdot3^{18}-2^{29}\cdot3^{20}}{5\cdot2^{28}\cdot3^{19}-7\cdot2^{29}\cdot3^{18}}\)
\(=\dfrac{2^{29}\cdot3^{18}\left(5\cdot2-9\right)}{2^{28}\cdot3^{18}\left(5\cdot3-7\cdot2\right)}=2\)
Tính : \(\dfrac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{5.2^9.2^{19}.3^{19}-7.2^{29}.3^{18}}\)
\(\dfrac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{5.2^9.2^{19}.3^{19}-7.2^{29}.3^{18}}=\dfrac{5.2^{30}.3^{18}-2^{29}.3^{20}}{2^{28}.3^{19}.5-7.2^{29}.3^{18}}=\dfrac{2^{29}.3^{18}\left(5.3+3^2\right)}{2^{28}.3^{18}\left(3.5+7.2\right)}=\dfrac{2.24}{29}=\dfrac{48}{29}\)
\(\dfrac{4^5+4^5+4^5+4^5+4^5+4^5}{3^5+3^n}.\dfrac{4.6^5}{2^5.2^5.2^5}=2^n\)
Tính n
rút gọn về phân số tối giản:
a, \(\dfrac{-147}{252}\) b,\(\dfrac{765}{900}\) c, \(\dfrac{11.3-11.8}{17-6}\) d,\(\dfrac{3^5.2^4}{8.3^6}\) e, \(\dfrac{84.45}{49.54}\)
RÚT GỌN VỀ PHÂN SỐ TỐI GIẢN
câu a) \(\dfrac{-147}{252}=\dfrac{-7}{12}\)
câu b) \(\dfrac{765}{900}=\dfrac{17}{20}\)
câu c) \(\dfrac{11\cdot3-11\cdot8}{17-6}=\dfrac{-5}{1}\)
câu d) \(\dfrac{3^5\times2^4}{8\times3^6}=\dfrac{2}{3}\)
câu e) \(\dfrac{84\cdot45}{49\cdot54}=\dfrac{10}{7}\)