B=2^6.3^5-9^2.4^3 phan 4^3.9^3-3^4.8^2
Thực hiện phép tính: \(B=\frac{2^6.3^5-9^2.4^3}{4^3.9^2-3^4.8^2}\)
\(=\frac{\left(2^2\right)^3.3^5-\left(3^2\right)^2.4^3}{\left(2^2\right)^3.9^2-\left(3^2\right)^2.\left(2^3\right)^2}=\frac{4^3.3^5-3^4.4^3}{2^6.9^2-9^2.2^6}=\frac{4^3.\left(3^5-3^4\right)}{9^2.\left(2^6-2^6\right)}=\frac{162}{0}\)
phps tính không hợp lệ vì không tồn taij phân số có mẫu bằng 0
1)tính 1 cách hợp lí: a) A=\(\left(\frac{1313}{1414}+\frac{10}{160}\right)-\left(\frac{130}{140}+\frac{1515}{1616}\right)\)
b)B=\(\left(\frac{2^6.3^5-9^2.4^3}{4^3.9^2-3^4.8^2}\right)\)
2)Chứng minh rằng:C=\(\frac{1}{101}+\frac{1}{102}+\frac{1}{103}+...+\frac{1}{200}>\frac{7}{12}\)
Mình làm luôn
a,A\(=\left(\frac{1313}{1414}-\frac{130}{140}\right)+\left(\frac{1515}{1616}+\frac{10}{160}\right)\)
\(=0+1\)
=1
b,Rút gọn p/s giống nhau ở tử và mẫu :26 với 82, 92 với 92, 35 với 34 thì còn3
Sau khi rút gọn rồi thì ta còn p/s:\(\frac{1.3-1.1}{1.1.1.1}=3\)
Câu 2 mình chịu
Rút gọn biểu thức:
a) \(\frac{3^7.5^4}{25^2}\)
b) \(\frac{2^4.2^6.3^8.9^2}{4^4.3^{11}}\)
c) \(\frac{3.9^4-9^3}{3^3.9}\)
Bạn nào biết chỉ mk với. Mk sẽ đãi hậu hĩnh luôn.
\(a,\frac{3^7.5^4}{25^2}=\frac{3^7.5^4}{\left(5^2\right)^2}=\frac{3^7.5^4}{5^4}=3^7\)
Ủa, bạn " Thám tử lừng danh conan " ơi? Sao chỉ có mỗi câu a thế???
a,-3/5.2/7+-3/7.3/5+-3/7
b,6^4.3^2.25^2-8^3.9^2.125/5^2.4^3.3^4
a,-3/5.2/7+-3/7.3/5+-3/7
=-3/7.2/5+(-3/7).3/5+(-3/7)
=-3/7(2/5+3/5+1)
=-3/7.2
=-6/7
\(\frac{-3}{5}\)và\(\frac{2}{7}\)mình đổi hai mẫu cho nhau
\(\frac{2^{15}.9^4}{6^6.3^3}+\frac{8^2.4^5}{2^{20}}\)
Tính
=\(\frac{2^{15}\cdot\left(3^2\right)^4}{2^6\cdot3^6.3^3}+\frac{\left(2^3\right)^2\cdot\left(2^2\right)^5}{2^{20}}\)
=\(\frac{2^9}{3}+\frac{1}{2^4}\)
=\(\frac{512}{3}+\frac{1}{16}=\frac{8192}{48}+\frac{3}{48}=\frac{8195}{48}\)
Tính nhanh:
1.2-2.4+3.6-4.8/ 4.12-3.9+2.6-1.3
a, Tính tổng: 5/6+5/12+5/20+.......+5/132
b, Tìm x: 1/2.4+1/4.6+......+1/x(x+2)
c,Tính tổng: -1/2 . -2/3 . -3/4..........-99/100
3/4.8/9.15/16.............9999/10000
3/4.8/9.15/16......9999/10000
= 3.8.15.....9999/4.9.16......10000
=101/50
a; \(\dfrac{5}{6}\) + \(\dfrac{5}{12}\) + \(\dfrac{5}{20}\) + ... + \(\dfrac{5}{132}\)
= 5.(\(\dfrac{1}{6}\) + \(\dfrac{1}{12}\) + \(\dfrac{1}{20}\) + ..+ \(\dfrac{1}{132}\))
= 5.(\(\dfrac{1}{2.3}\) + \(\dfrac{1}{3.4}\) + ... + \(\dfrac{1}{11.12}\))
= 5.(\(\dfrac{1}{2}\) - \(\dfrac{1}{3}\) + \(\dfrac{1}{3}\) - \(\dfrac{1}{4}\) + ...+ \(\dfrac{1}{11}\) - \(\dfrac{1}{12}\))
= 5.(\(\dfrac{1}{2}\) - \(\dfrac{1}{12}\))
= 5.(\(\dfrac{6}{12}\) - \(\dfrac{1}{12}\))
= 5.\(\dfrac{5}{12}\)
= \(\dfrac{25}{12}\)
b; \(\dfrac{1}{2.4}\) + \(\dfrac{1}{4.6}\) + ... + \(\dfrac{1}{x.\left(x+2\right)}\)
= \(\dfrac{1}{2}\) .(\(\dfrac{2}{2.4}\) + \(\dfrac{2}{4.6}\) + ... + \(\dfrac{2}{x\left(x+2\right)}\))
= \(\dfrac{1}{2}\).(\(\dfrac{1}{2}\) - \(\dfrac{1}{4}\) + \(\dfrac{1}{4}\) - \(\dfrac{1}{6}\) +...+ \(\dfrac{1}{x}\) - \(\dfrac{1}{x+2}\))
= \(\dfrac{1}{2}\).(\(\dfrac{1}{2}\) - \(\dfrac{1}{x+2}\))
= \(\dfrac{1}{2}\).\(\dfrac{x+2-2}{x+2}\)
= \(\dfrac{x+\left(2-2\right)}{2.\left(x+2\right)}\)
= \(\dfrac{x+0}{2\left(x+2\right)}\)
= \(\dfrac{x}{2.\left(x+2\right)}\)
Tính giá trị của biểu thức:
a) \(3^2.5^3+9^2;\)
b) \(8^3:4^2-5^2;\)
c) \(3^3.9^2-5^2.9+18:6.\)
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) 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
Bài 1:
a.35 1/6:(-4)/5-46 1/6:(-4)/5
b.1/6+5/6.3/2-3/2+1
c.-1/12-(2 5/8-1/3)
d.-5/4.8/9+-7/16.8/9-2
e.1/6.(-2 3/5)+1 2/5.(-13/5)
Bài 2
a.-5/8+x=(-2/3)^2
b.-1/4-3/4:x=-11/36
c.-22/15x+1/3=/-2/3-1/5/
d./-1/2-x/=1/3
e./2x+3/4/-6=-5
f.-5/7-/1/2-x/=-11/4
g.//x+5/-4/=3
h./17x-5/=/17x+5/
i./x-1/=2x-5
k.(x-1)^3=27
l.(2x-1)^2=25
n.5^x+2=625
m.(2x-1)^3=-8
o.x^2+x=0