Nguyễn Lâm
Giới thiệu về bản thân
Hello, please tick for me if you find my answers useful.
0
0
0
0
0
0
0
2022-11-10 20:54:46
\(\dfrac{2^3+2^4+2^5+2^6}{15^2}\)=\(\dfrac{2^3\left(1+2+4+8\right)}{15^2}\)= \(\dfrac{2^3.15}{15^2}\)= \(\dfrac{8}{15}\)
2022-11-06 15:12:28
|7x-5y|, |2z-3x| ≥ 0
Để |7x-5y| + |2z-3x| = 0
=> 7x - 5y = 2z - 3x = 0
=> 7x = 5y ; 2z = 3x
=> \(\dfrac{x}{5}\)=\(\dfrac{y}{7}\)
\(\dfrac{z}{3}\)=\(\dfrac{x}{2}\)
=> \(\dfrac{x}{10}\)=\(\dfrac{y}{14}\)=\(\dfrac{z}{15}\)
=> (\(\dfrac{x}{10}\))2 = \(\dfrac{xy}{140}\)= \(\dfrac{yz}{210}\)=\(\dfrac{xz}{150}\)=\(\dfrac{xy+yz+xz}{140+150+210}\)= 4
=> x = 20, y = 28, z = 30
2022-11-06 10:42:21
A = 1111 + 111111 + 11111111
A = ...1 + ...1 + ...1
A = ...3
Số chính phương ko tận cùng = 3
=> A ko là số chính phương