\(\dfrac{4}{7}-\dfrac{4}{7}+\dfrac{8}{21}+\dfrac{13}{21}+\left(-\dfrac{1}{2}\right)^2=\dfrac{1}{4}\)
\(\dfrac{4}{7}-\dfrac{4}{7}+\dfrac{8}{21}+\dfrac{13}{21}+\left(-\dfrac{1}{2}\right)^2=\dfrac{1}{4}\)
Thuc hien phep tinh;
a/ \(1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}\)
b/ \(\left(\dfrac{1}{25}+\dfrac{1}{5}+1\right):\left(\dfrac{1}{25}-\dfrac{1}{5}-1\right)\)
c/ \(\dfrac{\dfrac{1}{9}-\dfrac{1}{7}-\dfrac{1}{11}}{\dfrac{4}{9}-\dfrac{4}{7}-\dfrac{4}{11}}\)+ \(\dfrac{0,6-\dfrac{3}{25}-\dfrac{3}{125}-\dfrac{3}{625}}{\dfrac{4}{5}-0,16-\dfrac{4}{125}-\dfrac{4}{625}}\)
d/ \(\dfrac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\dfrac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)
1./Tìm x: (x+2)3 = 1/8
2./Chứng minh rằng:
a/2 . 22. 23 . 24 . 25 . ... . 299 . 2100 chia hết cho 3
b/55 -54 +53 chia hết cho 7
c/219 +221 +222 chia hết cho 13
Thực hiện phép tính (bằng cách hợp lí nếu có thể)
a) \(1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}\)
b) \(\dfrac{3}{7}.19\dfrac{1}{3}-\dfrac{3}{7}.33\dfrac{1}{3}\)
c) \(9.\left(\dfrac{1}{3}\right)^3+\dfrac{1}{3}\)
d) \(15\dfrac{1}{4}:\left(-\dfrac{5}{7}\right)-25\dfrac{1}{4}:\left(-\dfrac{5}{7}\right)\)
bài 1
27/23+5/21-4/23+16/21+1/2
3/2-5/6:(1/2)^2+ căn bậc 2 4
Bài 2: tính
a, \(\dfrac{11}{24}-\dfrac{5}{41}+\dfrac{13}{24}+0,5-\dfrac{36}{41}\)
b,\(-12:\left(\dfrac{3}{4}-\dfrac{5}{6}\right)^2\)
c,\(\dfrac{7}{23}.[\left(-\dfrac{8}{6}\right)-\dfrac{45}{18}]\)
d,\(23\dfrac{1}{4}.\dfrac{7}{5}-13\dfrac{1}{4}:\dfrac{5}{7}\)
e,\(\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right).\left(0,8-\dfrac{3}{4}\right)^2\)
Thực hiện phép tính bằng cách hợp lí
a) \(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-1\dfrac{15}{17}+\dfrac{2}{3}\)
b) \(\left(-2\right)^3.\left(\dfrac{3}{4}-0,25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
BÀI 1:Tính bằng cách hợp lý nhất: | BÀI 2:Tìm x biết:
a) 1\(\frac{4}{23}\)+\(\frac{5}{21}\)-\(\frac{4}{23}\)+0,5+\(\frac{16}{21}\) ; | a) |x+5|-6=9
b) \(23\frac{1}{4}\).\(\frac{7}{5}\)-13\(\frac{1}{4}\):\(\frac{5}{7}\) ; | b) \(\left(x-1\right)^2=25\)
c) \(\frac{2^4.2^6}{\left(2^5\right)^2}-\frac{2^5.15^3}{6^3.10^2}\) |
-------------------------------------------------------------------------------------------------------------------------------------------------------
BÀI 3:Tìm x biết:
a) \(\frac{x}{12}-\frac{5}{6}=\frac{1}{12}\) e) \(1\frac{1}{2}.x-4=0,5\)
b) \(\frac{2}{3}-1\frac{4}{15}x=\frac{-3}{5}\) f) 2x-1 =16
c) -23 +0.5x=1.5 g) (x-1)2 =25
d) \(\frac{\left(-3\right)^x}{81}=27\) h) |2x-1|=5
So sánh
a) 3*\(\sqrt{2}\) và 7, (21)
b) \(\frac{1}{\sqrt{1}+\sqrt{2}}\) + \(\frac{1}{\sqrt{2}+\sqrt{3}}+\frac{1}{\sqrt{3}+\sqrt{4}}+.....+\frac{1}{\sqrt{99}+\sqrt{100}}\) và 9
Tìm y biết :
a) \(-\dfrac{3}{5}.y=\dfrac{21}{10}\)
b) \(y:\dfrac{3}{8}=-1\dfrac{31}{33}\)
c) \(1\dfrac{2}{5}.y+\dfrac{3}{7}=-\dfrac{4}{5}\)
d) \(-\dfrac{11}{12}.y+0,25=\dfrac{5}{6}\)