Ta có: \(\frac{-1}{4}\cdot\frac{15}{49}-\left(\frac{80}{100}+\frac{2}{3}\right):2\frac{1}{5}\)
\(=\frac{-15}{196}-\left(\frac{240}{300}+\frac{200}{300}\right)\cdot\frac{5}{11}\)
\(=\frac{-15}{196}-\frac{440}{300}\cdot\frac{5}{11}\)
\(=\frac{-15}{196}-\frac{2}{3}\)
\(=\frac{-45}{588}-\frac{392}{588}=\frac{-437}{588}\)
\(1\dfrac{13}{15}\) . 0,75 - (\(\dfrac{104}{195}+25\%\) ) . \(\dfrac{24}{47}\) . \(3\dfrac{12}{13}\) : 3 + 1,4 . \(\dfrac{15}{49}\) - ( \(80\%+\dfrac{2}{3}\) ) \(:2\dfrac{1}{5}\)
\(1,4\cdot\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):2\dfrac{1}{5}\)
Thực hiện phép tính
\(a,(\frac{-5}{28}+1,75+\frac{8}{35}).(-3\frac{9}{20})\) \(b,(6-2\frac{4}{5}).3\frac{1}{8}-1\frac{3}{5}:\frac{1}{4}\)
\(c,(\frac{7-5}{24}+0,75+\frac{7}{12}):(-2\frac{1}{8})\) \(d,8\frac{2}{7}-(3\frac{4}{7}+4\frac{2}{7})\)
\(e,\left(-3,2\right).\frac{-15}{64}+(0,8-2\frac{4}{15}):3\frac{2}{3}\) \(f,1\frac{13}{15}.\left(0,5\right)^2.3+(\frac{8}{15}-1\frac{19}{60}):1\frac{23}{24}\)
\(g,1,4.\frac{15}{49}-(\frac{4}{5}+\frac{2}{3}):2\frac{1}{5}\)
Ai giúp không hứa sẽ tick nhiều . Làm đc phần nào thì đăng phần đó làm nhìu tick nhìu làm ít tick ít . Giúp ik
Tính nha
A = 1 . 3 + 3 . 5 + 5 . 7 + ... + 49 . 51
B = 2 . 4 + 4 . 6 + 6 . 8 + ... + 98 . 100
C = 1 . 4 + 4 . 7 + 7 . 10 + ... + 301 . 304
D = 1 + 1 . 1! + 2 . 2! + 3 . 3! + ... + 100 . 100!
E = 22 + 42 + ... + ( 2n )2
A=1-1/2+1/3-1/4+1/5-1/6+....+1/49-1/50. Chứng minh rằngA<5/6
Cho A= 1-1/2+1/3-1/4+ 1/5-1/6+....+1/49-1/50. Chứng minh A< 5/6
Bài 1. Thực hiện phép tính (Tính nhanh nếu có thể ) 1) 347.22 - 22. ( 216 + 184 ) : 8; 2) 132 - [116 - (132 - 128 )2] 3) 16 :{400 : [200 - ( 37 + 46. 3 )]}; 4) {184 : [96 - 124 : 31 ] - 2 }. 3651; 5) 46 - [ (16 + 71. 4 ) : 15 ]} - 2; 6) 33.18 + 72.42 - 41.18 7) ( 56. 46 – 25. 23 ) : 23; 8) ( 28. 54 + 56. 36 ) : 21 : 2; 9) ( 76. 34 - 19. 64 ) : (38. 9); 10) ( 2+ 4 + 6 +.. + 100).(36.333-108. 111) ; 11) ( 5. 411- 3.165 ): 410 ; 12)
Bài 2. Tính: A= [(- 8 ) + ( - 7 ) ] + ( -10); B = - ( - 299 ) + ( - 219 ) + ( -401 ) + 12 C = 555 + ( - 100) + ( -80) + ; D = + ( - 40 ) + 3150 + ( - 307) E= 98.42 - {50.[(18 - 23): 2 + 32 ]}; F = - 80 - [ - 130 - ( 12 - 4 )2] + 20080 G = 1000 + ( - 670 ) + 297 + (- 330); H = 1024 : 24 + 140 : ( 38 + 25) - 723 : 721 I = ; K = 219 +573 + 381 - 173 L = 36. 33 - 105. 11 + 22. 15; N = 160 - ( 2 3.52 - 6. 25 ) O = (44. 52. 60 ) : ( 11. 13.15 ); P = (217 +154). ( 3 19 - 217 ). ( 24 - 42) Q = 100 + 98 + 96 +... + 4 +2 - 97 - 95 -... - 3 - 1
Bài 3. Tìm x N biết: a) 280 - ( x - 140 ) : 35 = 270; b) (190 - 2x ) : 35 - 32 = 16; c) 720 : [ 41 - ( 2x - 5 ) ] = 23.5 d) ( x : 23 + 45 ). 37 - 22 = 24. 105; e) ( 3x - 4 ). ( x - 1 )3 = 0; f) 22x-1 : 4 = 83 g) x17 = x; h) ( x - 5 )4 = ( x - 5 )6 ; i) ( x + 2 ) 5 = 210 ; k ) 1 + 2 + 3 +... + x = 78 l) ( 3.x – 24). 73 = 2.74; n) 5x : 52 = 125; m) ( x + 1) 2 = ( x + 1)0 ; o) ( 2 + x ) + ( 4 + x ) + ( 6 + x ) +... + ( 52 + x ) = 780 ; p) 70 x, 80 x và x > 8 q) x 12, x 25, x 30 và 0 < x < 500
Bài 4. Tìm x Z biết: a) ( - x + 31 ) - 39 = - 69 ; b) - 121 - ( - 35 - x ) = 50; c) 17 + x - ( 352 - 400 ) = - 32 d) 2130 - ( x + 130 ) + 72 = - 64; e) ; f) ; g) h) ; i) ( x - 2 ) - ( -8 ) = - 137; k) 15-(- x + 18) = - 24 l) 12 - = -19; m) 10 -
Bài 5. Tìm n N biết: a) 8 ( n - 2 ); b) ( 2.n +1 ) ( 6 - n ); c) 3.n ( n - 1 ); d) ( 3.n + 5) ( 2.n +1)
Bài 6. Tìm x, yN để : a) ( x + 22 ) ( x + 1); b) ( 2x + 23 ) B ( x - 1); c) ( 3x + 1 ) ( 2x - 1) d) ( x - 2 ) ( 2y + 1 ) = 17; e ) xy + x + 2y = 5
Bài 7. Tìm các cặp số nguyên x, y biết a) ( x - 1 ) ( y + 2 ) = 7; b) x. ( y - 3 ) = - 12; c) xy - 3x - y = 0 d) xy + 2x + 2 y = -16
Bài 8. Bỏ dấu ngoặc rồi rút gọn biểu thức a) - ( - a + c - d ) - ( c - a + d ); b) - ( a + b - c + d ) + ( a - b - c -d ) c) a( b - c - d ) - a ( b + c - d ); d*) (a+ b).( c + d) - ( a + d ) ( b + c ) e*)( a + b ) ( c - d ) - ( a - b )(c + d); f*) ( a + b ) 2 - ( a - b ) 2
1, Tính
a, 2008 . 2008 - 2010 . 2006
b, \(\dfrac{232323.29}{23.292929}\)
c, \(\dfrac{\left(2^{17}+5^{17}\right).\left(3^{14}-5^{12}\right).\left(2^4-4^2\right)}{15^2+5^3+67^7}\)
2, So sánh \(\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{100}}\) với 1
a)(\(\dfrac{2}{9}\)(6x-\(\dfrac{3}{4}\))-3(\(\dfrac{1}{4}\)x-\(\dfrac{1}{5}\))=\(\dfrac{-8}{15}\)
b)\(\dfrac{3}{4}\)(x-\(\dfrac{8}{9}\))-5(x-\(\dfrac{11}{15}\))+\(\dfrac{1}{2}\)x=5\(\dfrac{1}{12}\)
c)\(\dfrac{2}{3}\)(-3x-\(\dfrac{6}{5}\))-\(\dfrac{5}{7}\)(\(\dfrac{49}{15}\)-14x)=-2\(\dfrac{1}{3}\)
d)(12\(\dfrac{7}{8}\)-10\(\dfrac{13}{8}\)):x-1\(\dfrac{7}{33}\):\(\dfrac{8}{11}\)=1\(\dfrac{2}{3}\)
