Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
#)Giải :
\(A=\frac{1}{2}-\frac{2}{3}+\frac{3}{4}-\frac{4}{5}+\frac{5}{6}-\frac{6}{7}-\frac{5}{6}+\frac{4}{5}-\frac{3}{4}+\frac{2}{3}-\frac{1}{2}\)
\(A=\left(\frac{1}{2}-\frac{1}{2}\right)+\left(-\frac{2}{3}+\frac{2}{3}\right)+\left(\frac{3}{4}-\frac{3}{4}\right)+\left(-\frac{4}{5}+\frac{4}{5}\right)+\left(\frac{5}{6}-\frac{5}{6}\right)-\frac{6}{7}\)
\(A=0+0+0+0+0-\frac{6}{7}\)
\(A=-\frac{6}{7}\)
\(\frac{6}{5}-\frac{1}{4}+\frac{4}{5}-\frac{3}{4}\)
\(=\left(\frac{6}{5}+\frac{4}{5}\right)-\left(\frac{1}{4}+\frac{3}{4}\right)\)
\(=2-1\)
\(=1\)
\(\frac{7}{9}-\frac{5}{12}+\frac{2}{9}-\frac{7}{12}\)
\(=\left(\frac{7}{9}+\frac{2}{9}\right)-\left(\frac{5}{12}+\frac{7}{12}\right)\)
\(=1-1\)
\(=0\)
các câu sau tương tự
A=1
B=0
C=ÂM 8/15
D=0
E=2
F=3/2
H=2/3
LẦN SAU CHO KHÓ SÍU NHA LỚP 5 CŨNG LÀM ĐC
1; = ( -4/10 + 3/10 ) : ( -2/5 + 2/3 ) = -1/10 : ( -6/15 + 10/15 ) = -1/10 : 4/15 = -1/10 . 15/4 = -15/40 = -3/8
2; = 25/2 . -5/7 + 39/4 + -3/2 . 5/7 = -125/14 + 39/4 + -15/14 = ( -125/14 + -15/14 ) + 39/4 = -10 + 39/4 = -40/4 + 39/4 = -1/4
3; = 5/52 + 35/52 + 40/52 = 40/52 + 40/52 = 80/52 = 20/13
4; = ( -39/52 + 20/52 ) . 7/2 - ( 117/52 + 32/52 ) . 7/2 = -19/52 . 7/2 - 149/52 . 7/2 = ( -19/52 + -149/52 ) . 7/2 = -168/52 .7/2 = -147/13
5; = ( 36/12 + -9/12 + 8/12 ) - ( -12/6 + -8/6 + -9/6 ) - ( 6/6 - 14/6 - 27/6 ) = 35/12 + 10/12 + 70/12 = 115/12
6; = -1/3 + -8/35 +-2/9 + -1/135 +4/5 +-4/9 +3/7 = (-1/3 + -2/9 + -4/9 ) + ( -8/35 + 4/5 + 3/7 ) + -1/135 = ( -1/3 + -2/3 ) + ( -8/35 + 28/35 + 15/35 ) + -1/135 = -1 + 1 + -1/135 = -1/135
a) \(\left(-\dfrac{2}{3}+\dfrac{3}{7}\right):\dfrac{4}{5}+\left(-\dfrac{1}{3}+\dfrac{4}{7}\right):\dfrac{4}{5}\)
\(=\left(-\dfrac{5}{21}\right):\dfrac{4}{5}+\left(\dfrac{5}{21}\right):\dfrac{4}{5}\)
\(=\left(-\dfrac{5}{21}+\dfrac{5}{21}\right):\dfrac{4}{5}\)
\(=0:\dfrac{4}{5}\)
\(=0\)
b) \(\dfrac{5}{9}:\left(\dfrac{1}{11}-\dfrac{5}{22}\right)+\dfrac{5}{9}:\left(\dfrac{1}{15}-\dfrac{2}{3}\right)\)
\(=\dfrac{5}{9}:\left(-\dfrac{3}{22}\right)+\dfrac{5}{9}:\left(-\dfrac{3}{5}\right)\)
\(=\dfrac{5}{9}:\left[\left(-\dfrac{3}{22}\right)+\left(-\dfrac{3}{5}\right)\right]\)
\(=\dfrac{5}{9}:\left(-\dfrac{81}{110}\right)\)
\(=-\dfrac{550}{729}\)
c) \(4^2.4^3:4^{10}\)
\(=\dfrac{4^5}{4^{10}}\)
\(=\dfrac{1}{4^5}\)
\(=\dfrac{1}{256}\)
d) \(\left(0,6\right)^5:\left(0,2\right)^6\)
\(=\dfrac{\left(0,2\cdot3\right)^5}{\left(0,2\right)^6}\)
\(=\dfrac{\left(0,2\right)^5\cdot3^5}{\left(0,2\right)^6}\)
\(=\dfrac{243}{0,2}\)
\(=1215\)
Mai mốt bạn đăng một lần ít thôi nha tại giờ khuya quá nên mình chỉ làm đến đây thôi =))
\(3\frac{1}{2}-4\frac{2}{3}\cdot\left(\frac{3}{4}-2\frac{1}{3}\right)-\left(\frac{5}{6}-\frac{7}{4}\right)+5\frac{1}{2}-3\)
\(=\frac{7}{2}-\frac{14}{3}\cdot\left(\frac{3}{4}-\frac{7}{3}\right)-\left(\frac{5}{6}-\frac{7}{4}\right)+\frac{11}{2}-3\)
\(=\frac{7}{2}-\frac{14}{3}\cdot\left(-\frac{19}{12}\right)+\frac{11}{12}+\frac{11}{2}-3\)
\(=\frac{7}{2}+\frac{133}{198}+\frac{77}{12}-3\)
\(=\frac{3005}{396}\)