Câu 1:
Câu hỏi của Trần Văn Thành - Toán lớp 6 - Học toán với OnlineMath
Hoàng Thị Ngọc Anh đề khác hoàn toàn mà mi
Bài 1: tính M :N biết:
a) N=\(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+.......+\dfrac{1}{2007}+\dfrac{1}{2008}\) và M= \(\dfrac{2007}{1}+\dfrac{2006}{2}+\dfrac{2005}{3}+.......+\dfrac{2}{2006}+\dfrac{1}{2007}\)
b) M= \(\dfrac{1}{11.13}+\dfrac{1}{13.15}+\dfrac{1}{15.17}+.......+\dfrac{1}{31.33}+\dfrac{1}{33.35}\) và N= \(\dfrac{12}{11.13.15}+\dfrac{12}{13.15.17}+\dfrac{12}{15.17.19}+.....+\dfrac{12}{31.33.35}\)
Tìm x biết
1, \(\dfrac{-1}{4}-\dfrac{3}{4}:x=-\dfrac{11}{36}\)
2,\(\dfrac{3}{4}x-\dfrac{1}{2}=\dfrac{3}{7}\)
1. Tìm tỉ số \(\dfrac{x}{y}\) biết \(\dfrac{2x-y}{x+y}\)=\(\dfrac{2}{3}\)
2. Tìm x:
a) 3,8 : (2x) = \(\dfrac{1}{4}:2\dfrac{2}{3}\)
b) \(1\dfrac{1}{3}\) : 0,8 = \(\dfrac{2}{3}\) : (0,1x)
c) \(\dfrac{x}{-15}\) = \(\dfrac{-60}{x}\)
d) \(\dfrac{-2}{x}=\dfrac{-x}{\dfrac{8}{25}}\)
e) 0,2 : \(1\dfrac{1}{5}\)= \(\dfrac{2}{3}\) : (6x+7)
3. Tính A = \(\dfrac{8^{10}+4^{10}}{8^4+4^{11}}\)
Tìm x,y,z bt
\(1.\dfrac{x}{3}=\dfrac{y}{6};4x-y=42\)
\(2.\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{5};x-2y+3z=33\)
\(3.\dfrac{x}{y}=\dfrac{6}{5};x+y=121\)
5. \(3-1\dfrac{1}{2}-x+\dfrac{5}{4}=2-\left|1\dfrac{1}{8}-\dfrac{5}{12}\right|\) 6. \(3\dfrac{1}{14}-5\dfrac{1}{3}-\dfrac{4}{7}+\dfrac{11}{21}=x-\dfrac{1}{2}\) 7. \(\dfrac{11}{-40}+\dfrac{4}{5}-\left|\dfrac{3}{4}-1\dfrac{5}{12}\right|=\dfrac{3}{20}-x\)
5. \(3-1\dfrac{1}{2}-x+\dfrac{5}{4}=2-\left|1\dfrac{1}{8}-\dfrac{5}{12}\right|\) 6. \(3\dfrac{1}{14}-5\dfrac{1}{3}-\dfrac{4}{7}+\dfrac{11}{21}=-\dfrac{1}{2}\) 7. \(\dfrac{11}{-40}+\dfrac{4}{5}-\left|\dfrac{3}{4}-1\dfrac{5}{12}\right|=\dfrac{3}{20}-X\)
Tìm x,y,z biết :
1) \(x:y:z=3:5:\left(-2\right)\) và \(5x-y+3z=-16\)
2) \(\dfrac{x}{2}=\dfrac{y}{-3};\dfrac{z}{3}=\dfrac{y}{4}\) và \(x+y+z=5,2\)
3) \(2x=3y;7z=5y\) và \(3x-7y+5z=30\)
4) \(3x=4y=5z\) và \(x-\left(y+z\right)=-21\)
5) \(\dfrac{x-1}{2}=\dfrac{y-2}{3}=\dfrac{z-3}{4}\) và \(2x+3y-z=50\)
Câu 1. 1- (x + \(\dfrac{1}{3}\) )\(^2\) = \(\dfrac{5}{9}\)
Câu 2. 15 :( \(\dfrac{4}{9}\))\(^2\) . (\(\dfrac{8}{27}\))\(^2\) : (\(\dfrac{2}{3}\))\(^9\)
tìm x :
a) \(\dfrac{x+1}{7}+\dfrac{x+1}{8}=\dfrac{x+1}{9}+\dfrac{x+1}{10}\)
b) \(\dfrac{x+1}{12}+\dfrac{x^2}{11}=\dfrac{x+3}{10}+\dfrac{x+4}{9}\)
c) \(\dfrac{x-2}{x-1}=\dfrac{x+4}{x+7}\)
d)\(\dfrac{3x+2}{5x+7}=\dfrac{3x-1}{5x-3}\)
2 tìm x,y,z
a) \(\dfrac{x}{2}=\dfrac{y}{3},\dfrac{y}{4}=\dfrac{z}{5}vàx^2-y^2=-16\)
b)2x=3y,5x=7z và 3x-7y+5z=30
