Đại số lớp 6
Các câu hỏi tương tự
Tìm n
1/2 x 2^n + 4 x 2^n = 9 x 5^n
Tính hợp lý
a) A= ( 2^8 + 3^8) : ( 2^5 x 2^3)
b) B = ( 2^17 + 17^2) x (9^15 - 15^9) x (4^2 - 2^4)
BT1: Tính nhanh
1) \(\left(\dfrac{-4}{9}+\dfrac{3}{7}\right):1\dfrac{1}{15}+\left(\dfrac{4}{7}-\dfrac{5}{9}\right):1\dfrac{1}{15}\)
2) \(3\dfrac{2}{9}.15\dfrac{4}{7}-3\dfrac{2}{9}.8\dfrac{1}{7}+3\dfrac{2}{9}.\dfrac{15}{7}-3\dfrac{2}{9}.\dfrac{1}{7}\)
Cho A = 1/2^2 + 1/2^3 +...............+1/9^2
CMR 8/9>A>2/5
bài 1 : sắp xếp theo thứ tự tăng dần : \(\frac{1}{2};\frac{1}{3};\frac{1}{38};\frac{-1}{12};\frac{-7}{9};\frac{-6}{9};0;\frac{9}{11};\frac{3}{2}\)
Tim x biet
A, 5/9 + x/-1 = -1/3
B, 1/5 + 2/20 + 121/165 <x< 1/2 + 156/72 + 1/3 ( x thuoc N)
C, x + 5/3 = 1/81
D, x-1/3 + 3x-5/2 + 2x/9 + -5x+3/9 = 210/420
2/5-2/9+2/11/7/5-7/9+7/11:1/3-1/4+1/5/7/6-7/8+7/10:tính nhanh
k.(2x+3/5)2-9/25=0
l.3(3x-1/2)3+1/9=0
b) Cho S = \(\dfrac{1}{2^2}+\dfrac{1}{3^2}+...+\dfrac{1}{9^2}\). Chứng minh rằng \(\dfrac{2}{5}< S< \dfrac{8}{9}\)
Cho \(A=\dfrac{1}{2^2}+\dfrac{1}{3^2}+\dfrac{1}{4^2}+................+\dfrac{1}{9^2}\)
Chứng minh \(\dfrac{2}{5}< A< \dfrac{8}{9}\)
Help me!!!!!!!!!!! tôi đang cần gấp!!!