1) co bao nhieu boi cua 4 tu 10 den 200

2) co bao nhieu so vua la boi cua 5 vua la uoc cua 50

3) tim cac so tu nhien N sao cho : 

A) N-1 la uoc cua 28

B) 2 nhan N +1 la uoc cua 18

C) N nhan (N +2)=8 

3 like cho nguoi giai nhanh nhat 3 cau tren . Giai ki nhe 

mot cong nhan , trong mot thang tien an chiem het \(\frac{1}{2}\)tien luong , tien nha chiem het \(\frac{1}{6}\)tien luong va tien tieu vat bang \(\frac{1}{5}\)tien luong , cuoi thang nguoi cong nhan de danh duoc 200.000 dong.hoi luong thang cua nguoi cong nhan la bao nhieu?

goi y luong thang nguoi cong nhan la : 600.000

ai lam xong va dung cho 3 tich.

rut gon phan so 

15 nhan 64 phan 16 nhan 40 

2 nhan 3 nhan 5 phan 70 

21 nhan 45 phan 9 nhan 7 nhan 5 nhan 3

rut gon \(y=\frac{2x+2}{\sqrt{x}}+\frac{x\sqrt{x}-1}{x-\sqrt{x}}-\frac{x^2+\sqrt{x}}{x\sqrt{x}+x}\)

cmr voi moi gia tri cua x de Y co nghia thi bieu thuc \(\frac{7}{y}\)chi nhan moi gia tri nguyen

tinh hop li :

                 \(\frac{\left(\frac{1}{5}-\frac{2}{7}\right)\cdot\frac{3}{4}-\frac{3}{4}\cdot\left(\frac{1}{3}-\frac{2}{7}\right)}{\frac{1}{5}\cdot\frac{2}{7}-\frac{1}{3}\cdot\left(\frac{2}{7}+\frac{3}{9}\right)+\frac{3}{9}+\frac{1}{5}}\)

cham la nhan nha cac ban 

ai nhanh mk tick cho

cho A=1+7+7²+...+7²⁰¹⁷

a/ chung to rang A chia het cho 8

b/ rut gon A

c/ tim chu so tan cung cua A

BAI 2

cho M=1 nhan 2+2 nhan 3+3 nhan 4+....+2015 nhan 2015

a/ rut gon M

b/ su dung ket qua cua a tinh D=2²+4²+6²+...+2014²

co cau hoi nay ai lam dc giup minh

2 nhan 4 nhan nhan 8 nhan 10 nhan 12 den .....................nhan 3260

Cho bieu thuc P = \(\frac{x-\sqrt{x}}{x+\sqrt{x}+1}\) --\(\frac{2x+\sqrt{x}}{\sqrt{x}}\)+\(\frac{2\left(x-1\right)}{\sqrt{x}-1}\)

a) rut gon P

b) tim x de Q=\(\frac{2\sqrt{x}}{P}\)nhan gia tri nguyen