\(\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^2}-\frac{5^{10}.7^3-25^3.4...">
K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

9 tháng 7 2017

Đặt d=ƯCLN(12n+1;30n+2)

=>12n+1 chia hết cho d; 30n+2 chia hết cho d

=>5(12n+1) chia hết cho d; 2(30n+2) chia hết cho d

=>60n+5 chia hết cho d; 60n+4 chia hết cho d

=>(60n+5)-(60n+4) chia hết cho d

=>1 chia hết cho d

=>d=1

=>phân số \(\frac{12n+1}{30n+2}\) là phân số tối giản 

8 tháng 7 2017

Bài 1:

\(\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^2}-\frac{5^{10}.7^3-25^3.49^2}{\left(125.7\right)^3+5^9.14^3}=\frac{2^{12}.3^5-\left(2^2\right)^6.\left(3^2\right)^2}{2^{12}.3^6+\left(2^3\right)^4.3^2}-\frac{5^{10}.7^3-\left(5^2\right)^3.\left(7^2\right)^2}{\left(5^3.7\right)^3+5^9.2^3.7^3}\)

\(=\frac{2^{12}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^2}-\frac{5^{10}.7^3-5^6.7^4}{5^9.7^3+5^9.2^3.7^3}=\frac{2^{12}.3^4\left(3-1\right)}{2^{12}.3^2\left(3^4+1\right)}-\frac{5^6.7^3\left(5^4-7\right)}{5^9.7^3\left(1+2^3\right)}=\frac{3^2.2}{82}-\frac{618}{5^3.9}\)

\(=\frac{9}{41}-\frac{206}{375}=\)

15 tháng 7 2017

\(\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\frac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)

\(=\frac{2^{12}.3^5-\left(2^2\right)^6.\left(3^2\right)^2}{2^{12}.3^6+\left(2^3\right)^4.3^5}-\frac{5^{10}.7^3-\left(5^2\right)^5.\left(7^2\right)^2}{\left(5^3.7\right)^3+5^9.\left(2.7\right)^3}\)

\(=\frac{2^{12}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}-\frac{5^{10}.7^3-5^{10}.7^4}{5^9.7^3+5^9.2^3.7^3}\)

\(=\frac{2^{12}.3^4\left(3-1\right)}{2^{12}.3^5\left(3+1\right)}-\frac{5^{10}.7^3.\left(1-7\right)}{5^9.7^3\left(1+2^3\right)}\)

\(=\frac{2^{12}.3^4.2}{2^{12}.3^5.4}-\frac{5^{10}.7^3.\left(-6\right)}{5^9.7^3.9}\)

\(=\frac{1}{6}-\frac{-10}{3}=\frac{1}{6}+\frac{10}{3}=\frac{1}{6}+\frac{20}{6}=\frac{21}{6}=\frac{7}{2}\)

9 tháng 1 2018

lam nhu stctv ay dung day to thu lam roi

30 tháng 12 2018

a hơi dài để làm phần b trước :

\(3^{n+2}-2^{n+2}+3^n-2^n\)

\(=3^n\cdot3^2-2^n\cdot2^2+3^n-2^n\)

\(=\left(3^n\cdot3^2+3^n\right)-\left(2^n\cdot2^2+2^n\right)\)

\(=3^n\cdot\left(3^2+1\right)-2^n\cdot\left(2^2+1\right)\)

\(=3^n\cdot10-2^n\cdot5\)

\(=3^n\cdot10-2^{n-1}\cdot2\cdot5\)

\(=3^n\cdot10-2^{n-1}\cdot10\)

\(=10\cdot\left(3^n-2^{n-1}\right)⋮10\left(đpcm\right)\)

30 tháng 12 2018

\(A=\frac{2^{12}.3^5-4^6.9^2}{\left(2^3.3\right)^6+8^4.3^5}-\frac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)

\(A=\frac{2^{12}.3^5-\left(2^2\right)^6.\left(3^2\right)^2}{\left(2^3.3\right)^6+\left(2^3\right)^4.3^5}-\frac{5^{10}.7^3-\left(5^2\right)^5.\left(7^2\right)^2}{\left(5^3.7\right)^3+5^9.\left(2.7\right)^3}\)

\(A=\frac{2^{12}.3^5-2^{12}.3^4}{2^{18}.3^6+2^{12}.3^5}-\frac{5^{10}.7^3-5^{10}.7^4}{5^9.7^3+5^9.2^3.7^3}\)

\(A=\frac{2^{12}.3^4\left(3-1\right)}{2^{12}.3^5.\left(2^6-1\right)}-\frac{5^{10}.7^3.\left(1-7\right)}{5^9.7^3\left(1+2^3\right)}\)

\(A=\frac{2}{3.\left(64-1\right)}-\frac{5.\left(-6\right)}{9}\)

\(A=\frac{2}{3.63}+\frac{30}{9}\)

Tự lm tiếp Ball nhé~

22 tháng 1 2017

\(\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\frac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}=\frac{2^{12}.3^5-\left(2^2\right)^6.\left(3^2\right)^2}{2^{12}.3^6+\left(2^3\right)^4.3^5}-\frac{5^{10}.7^3-\left(5^2\right)^5.\left(7^2\right)^2}{\left(5^3.7\right)^3+5^9.2^3.7^3}\)

\(=\frac{2^{12}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}-\frac{5^{10}.7^3-5^{10}.7^4}{5^9.7^3+5^9.2^3.7^3}=\frac{2^{12}.3^4\left(3-1\right)}{2^{12}.3^5\left(3+1\right)}-\frac{5^{10}.7^3\left(1-7\right)}{5^9.7^3\left(1+2^3\right)}=\frac{2}{3.4}-\frac{5.\left(-6\right)}{9}\)

\(=\frac{1}{6}-\frac{-10}{3}=\frac{1}{6}-\frac{-20}{6}=\frac{21}{6}=\frac{7}{2}\)

Lẽ ra là làm xong cho bạn rồi, vậy mà tự nhiên máy sập, giờ chép lại, oải quá :|

22 tháng 1 2017

ban giai duoc bai giup minh di minh chi cho

19 tháng 9 2016

\(A=\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\frac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)

\(\Rightarrow A=\frac{2^{12}.3^5-\left(2^2\right)^6.\left(3^2\right)^2}{2^{12}.3^6+\left(2^3\right)^4.3^5}-\frac{5^{10}.7^3-\left(5^2\right)^5.\left(7^2\right)^2}{\left(5^3.7\right)^3+5^9.\left(2.7\right)^3}\)

\(\Rightarrow A=\frac{2^{12}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}-\frac{5^{10}.7^3-5^{10}.7^4}{5^9.7^3+5^9.7^3.2^3}\)

\(\Rightarrow A=\frac{2^{12}.3^4\left(3-1\right)}{2^{12}.3^5\left(3+1\right)}-\frac{5^{10}.7^3\left(1-4\right)}{5^9.7^8\left(1+2^3\right)}\)

\(\Rightarrow A=\frac{2}{3.4}-\frac{5.\left(-3\right)}{9}\)

\(\Rightarrow A=\frac{1}{3}-\frac{-15}{9}\)

\(\Rightarrow A=\frac{1}{3}+\frac{5}{3}\)

\(\Rightarrow A=\frac{6}{3}=2\)

Vậy \(A=2\)

\(A=\dfrac{2^{12}\cdot3^5-2^{12}\cdot3^4}{2^{12}\cdot3^6+2^{12}\cdot3^5}-\dfrac{5^{10}\cdot7^3-5^{10}\cdot7^4}{5^9\cdot7^3+5^9\cdot7^3\cdot8}\)

\(=\dfrac{3^4\cdot\left(3-1\right)}{3^5\left(3+1\right)}-\dfrac{5^{10}\cdot7^3\cdot\left(-6\right)}{5^9\cdot7^3\cdot9}=\dfrac{2}{3\cdot4}-\dfrac{5\cdot\left(-2\right)}{3}\)

\(=\dfrac{1}{6}+\dfrac{10}{3}=\dfrac{1}{6}+\dfrac{20}{6}=\dfrac{21}{6}=\dfrac{7}{2}\)

7 tháng 11 2017

A = \(\frac{2^{12}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}\)\(\frac{5^{10}.7^3-5^{10}.7^4}{5^9.7^3+5^9.7^6}\)

    = \(\frac{2^{12}.3^4\left(3-1\right)}{2^{12}.3^5\left(3+1\right)}-\frac{5^{10}.7^3.\left(1-7\right)}{5^9.7^3.\left(1+2^3\right)}\) = \(\frac{2}{3.4}-\frac{5.\left(-6\right)}{9}\)\(\frac{1}{6}-\frac{-10}{3}\)= 1/6 + 10/3 = 7/2

7 tháng 1 2018

7/2 la dung

a:Sửa đề:  \(A=\dfrac{2^{12}\cdot3^5-2^{12}\cdot3^3}{2^{12}\cdot3^6+2^{12}\cdot3^5}-\dfrac{5^{10}\cdot7^3-25^5\cdot7^4}{5^9\cdot7^3+5^9\cdot2^3\cdot7^3}\)

\(=\dfrac{2^{12}\cdot3^3\cdot\left(3^2-1\right)}{2^{12}\cdot3^5\left(3+1\right)}-\dfrac{5^{10}\cdot7^3-5^{10}\cdot7^4}{5^9\cdot7^3\cdot9}\)

\(=\dfrac{1}{9}\cdot\dfrac{8}{4}-\dfrac{5^{10}\cdot7^3\cdot\left(1-7\right)}{5^9\cdot7^3\cdot9}\)

\(=\dfrac{2}{9}-\dfrac{5\cdot\left(-2\right)}{3}=\dfrac{2}{9}+\dfrac{10}{3}=\dfrac{2+30}{9}=\dfrac{32}{9}\)

b: Sửa đề: \(3^{n+2}-2^{n+2}+3^n-2^n\)

\(=3^n\cdot9+3^n-2^n\cdot4-2^n\)

\(=3^n\cdot10-2^n\cdot5\)

\(=10\left(3^n-2^{n-1}\right)⋮10\)

12 tháng 4 2019

a) A=\(\frac{2^{13}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\frac{5^{10}.7^5-25^3.49^2}{\left(125.7\right)^3+5^9.14^3}\) =\(\frac{2^{13}.3^5-\left(2^2\right)^6.\left(3^2\right)^2}{\left(2^2\right)^6.3^6+\left(2^3\right)^4.3^5}-\frac{5^{10}.7^5-\left(5^2\right)^3.\left(7^2\right)^2}{\left(5^3\right)^3.7^3+5^9.\left(2.7\right)^3}\) =\(\frac{2^{13}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}-\frac{5^{10}.7^5-5^6.7^4}{5^9.7^3+5^9.2^3.7^3}\) =\(\frac{2^{12}.3^4.\left(2.3-1\right)}{2^{12}.3^5.\left(6+1\right)}-\frac{5^6.7^4.\left(5^4.7-1\right)}{2^3.5^9.7^3\left(1+1.2^3\right)}\) =\(\frac{2^{12}.3^4.5}{2^{12}.3^5.7}-\frac{5^6.7^4.4374}{3^3.5^9.7^3.9}\) =\(\frac{5}{3.7}-\frac{7.4374}{3^3.5^3.3^2}\) =\(\frac{5}{21}-\frac{7.4374}{3^6.5^3}\) =\(\frac{5}{21}-\frac{7.4374}{729.125}\) =\(\frac{5}{21}-\frac{42}{125}\) =\(\frac{-257}{2625}\) b)S=\(2^2+4^2+....+20^2\) =\(\left(1.2\right)^2+\left(2.2\right)^2+....+\left(10.2\right)^2\) =\(2^2.\left(2^2+4^2+....+10^2\right)\) =\(2^2.385\) =4.385 =\(1540\)