8) ( 1/4 - 1/4 + 1/9 / 1/9 ) : ( 2/3 + 7/15 / 2/5 - 1/6 )
9) ( ( 2/193 - 3/389 ) . 193/17 + 33/34 ) : (( 7/1931 - 11 / 3862 ) . 1931 / 25 + 9/2 )
chú ý :
/ là phần nha , nếu có 2 cái (( là sẽ có ngoặc vuông nha ! nhanh nha mình đang gấp lắm
bài 1 : tính
1) 5/8 . 7/3 - 5/2 . 1/8 2) 21/10 . 3/4 - 21/10 - 3/4 3) -4 / 11 : -6/11 4) 2/7 . 14/3 -1 5) 4/7 : ( 1/5 . 4/7 ) 6) 12/7 . 7/4 + 35/11 : 245/121
7) ( 4/3 + 8/3 ) . ( 7/4 - 6/4 ) : ( 6/5 + 12/5 + 1/5 ) 8) ( 1/4 - 1/4 + 1/9 / 1/9 ) : ( 2/3 + 7/15 / 2/5 - 1/6 )
9) ( ( 2/193 - 3/389 ) . 193/17 + 33/34 ) : (( 7/1931 - 11 / 3862 ) . 1931 / 25 + 9/2 )
chú ý :
/ là phần nha , nếu có 2 cái (( là sẽ có ngoặc vuông nha ! nhanh nha mình đang gấp lắm
1) \(\frac{5}{8}.\frac{7}{3}-\frac{5}{2}.\frac{1}{8}=\frac{5}{8}.\frac{7}{3}-\frac{5}{8}.\frac{1}{2}=\frac{5}{8}\left(\frac{7}{3}-\frac{1}{2}\right)=\frac{5}{8}.\frac{11}{6}=\frac{55}{48}\)
2) \(\frac{21}{10}.\frac{3}{4}-\frac{21}{10}.\frac{3}{4}=\frac{21}{10}\left(\frac{3}{4}-\frac{3}{4}\right)=\frac{21}{10}.0=0\)
3) \(\frac{-4}{11}:\frac{-6}{11}=\frac{-4}{11}.\frac{-11}{6}=\frac{-4.\left(-11\right)}{11.6}=\frac{-4.\left(-1\right)}{1.6}=\frac{4}{6}=\frac{2}{3}\)
4)\(\frac{2}{7}.\frac{14}{3}-1=\frac{2.14}{7.3}-1=\frac{2.2}{1.3}-1=\frac{4}{3}-1=\frac{1}{3}\)
5)\(\frac{4}{7}:\left(\frac{1}{5}.\frac{4}{7}\right)=\frac{4}{7}:\frac{4}{35}=\frac{4}{7}.\frac{35}{4}=\frac{4.35}{7.4}=\frac{1.5}{1.1}=5\)
6) \(\frac{12}{7}.\frac{7}{4}+\frac{35}{11}:\frac{245}{121}=\frac{12.7}{7.4}+\frac{35}{11}.\frac{121}{245}=\frac{3.1}{1.1}+\frac{35}{11}.\frac{121}{245}=3+\frac{35}{11}.\frac{121}{245}=3+\frac{35.121}{11.245}=\frac{1.11}{1.7}=\frac{11}{7}\)
bài 1 : tính
1) 5/8 . 7/3 - 5/2 . 1/8 2) 21/10 . 3/4 - 21/10 - 3/4 3) -4 / 11 : -6/11 4) 2/7 . 14/3 -1 5) 4/7 : ( 1/5 . 4/7 ) 6) 12/7 . 7/4 + 35/11 : 245/121
7) ( 4/3 + 8/3 ) . ( 7/4 - 6/4 ) : ( 6/5 + 12/5 + 1/5 ) 8) ( 1/4 - 1/4 + 1/9 / 1/9 ) : ( 2/3 + 7/15 / 2/5 - 1/6 )
9) ( ( 2/193 - 3/389 ) . 193/17 + 33/34 ) : (( 7/1931 - 11 / 3862 ) . 1931 / 25 + 9/2 )
chú ý :
/ là phần nha , nếu có 2 cái (( là sẽ có ngoặc vuông nha ! nhanh nha mình đang gấp lắm
Bài 1: Tính
\(\text{1)}\) \(\dfrac{5}{8}.\dfrac{7}{30}-\dfrac{5}{2}.\dfrac{1}{8}\)
\(=\dfrac{5}{8}.\dfrac{7}{30}-\dfrac{5}{8}.\dfrac{1}{2}\)
\(=\dfrac{5}{8}.\left(\dfrac{7}{30}-\dfrac{1}{2}\right)\)
\(=\dfrac{5}{8}.\dfrac{-4}{15}\)
\(=\dfrac{-1}{6}\)
\(\text{2)}\) \(\dfrac{21}{10}.\dfrac{3}{4}-\dfrac{21}{10}-\dfrac{3}{4}\)
\(=\dfrac{63}{40}-\dfrac{21}{10}-\dfrac{3}{4}\)
\(=\dfrac{-21}{40}-\dfrac{3}{4}\)
\(=\dfrac{-51}{40}\)
\(\text{3)}\) \(\dfrac{-4}{11}:\dfrac{-6}{11}\)
\(=\dfrac{-4}{11}.\dfrac{11}{-6}\)
\(=\dfrac{4}{6}\)
\(\text{4)}\) \(\dfrac{2}{7}.\dfrac{14}{3}-1\)
\(=\dfrac{4}{3}-1\)
\(=\dfrac{1}{3}\)
\(\text{5)}\) \(\dfrac{4}{7}:\left(\dfrac{1}{5}.\dfrac{4}{7}\right)\)
\(=\dfrac{4}{7}:\dfrac{1}{5}:\dfrac{4}{7}\)
\(=1:\dfrac{1}{5}\)
\(=5\)
\(\text{6)}\) \(\dfrac{12}{7}.\dfrac{7}{4}+\dfrac{35}{11}:\dfrac{245}{121}\)
\(=3+\dfrac{35}{11}.\dfrac{121}{245}\)
\(=3+\dfrac{11}{7}\)
\(=3\dfrac{11}{7}=\dfrac{32}{7}\)
\(\text{7)}\) \(\left(\dfrac{4}{3}+\dfrac{8}{3}\right).\left(\dfrac{7}{4}-\dfrac{6}{4}\right):\left(\dfrac{6}{5}+\dfrac{12}{5}+\dfrac{1}{5}\right)\)
\(=4.\left(\dfrac{7}{4}-\dfrac{6}{4}\right):\left(\dfrac{6}{5}+\dfrac{12}{5}+\dfrac{1}{5}\right)\)
\(=4.\dfrac{1}{4}:\left(\dfrac{6}{5}+\dfrac{12}{5}+\dfrac{1}{5}\right)\)
\(=4.\dfrac{1}{4}:\dfrac{19}{5}\)
\(=1:\dfrac{19}{5}\)
\(=\dfrac{5}{19}\)
\(\text{8)}\) \(\left(\dfrac{1}{4}-\dfrac{1}{4}+\dfrac{\dfrac{1}{9}}{\dfrac{1}{9}}\right):\left(\dfrac{2}{3}+\dfrac{\dfrac{7}{15}}{\dfrac{2}{5}}-\dfrac{1}{6}\right)\)
\(=\left(0+1\right):\left(\dfrac{2}{3}+\dfrac{7}{15}:\dfrac{2}{5}-\dfrac{1}{6}\right)\)
\(=1:\left(\dfrac{2}{3}+\dfrac{7}{6}-\dfrac{1}{6}\right)\)
\(=1:\left(\dfrac{2}{3}+1\right)\)
\(=1:\dfrac{5}{3}\)
\(=\dfrac{3}{5}\)
\(\text{9)}\)
\(\left[\left(\dfrac{2}{193}-\dfrac{3}{389}\right).\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\left(\dfrac{7}{1931}-\dfrac{11}{3862}\right).\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
\(=\left[\dfrac{199}{75077}.\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\left(\dfrac{7}{1931}-\dfrac{11}{3862}\right).\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
\(=\left[\dfrac{199}{6613}+\dfrac{33}{34}\right]:\left[\left(\dfrac{7}{1931}-\dfrac{11}{3862}\right).\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
\(=\dfrac{13235}{13226}:\left[\left(\dfrac{7}{1931}-\dfrac{11}{3862}\right).\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
\(=\dfrac{13235}{13226}:\left[\dfrac{3}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
\(=\dfrac{13235}{13226}:\left[\dfrac{3}{50}+\dfrac{9}{2}\right]\)
\(=\dfrac{13235}{13226}:\dfrac{114}{25}\)
\(=\dfrac{330875}{1507764}\)
E=-66(1/2-1/3+1/11)+124.(-37)+63.(-124)
G=[(2/193-3/386).193/17+33/34]chia[(7/1931+11/3862).1931/25+9/2]
E = [193/-17 ( 2/193 - 3/386 ) + 11/34] : [(7/1931 + 11/3862) 1931/25 +9/2]
a)(1-1/2)(1-1/3)......(1-1/10)<1/9
b)(1-1/5)(1-1/5)(1-3/5)......(1-9/5)=0
c)[(2/193-3/386)193/17+33/34]:[(7/1931-11/3892)-1931/2+9/2]
Tính:
\(\left(\left(\frac{2}{193}-\frac{3}{386}\right).\frac{193}{17}+\frac{33}{34}\right):\left(\left(\frac{7}{1931}+\frac{11}{3862}\right).\frac{1931}{25}+\frac{9}{2}\right)\)
\(\left(\left(\frac{2}{193}-\frac{3}{386}\right).\frac{193}{17}+\frac{33}{34}\right):\left(\left(\frac{7}{1931}+\frac{11}{3862}\right)\cdot\frac{1931}{25}+\frac{9}{2}\right)\)
= \(\left(\left(\frac{4}{386}-\frac{3}{386}\right)\cdot\frac{193}{17}+\frac{33}{34}\right):\left(\left(\frac{14}{3862}+\frac{11}{3862}\right)\cdot\frac{1931}{25}+\frac{9}{2}\right)\)
= \(\left(\frac{1}{186}\cdot\frac{193}{17}+\frac{33}{34}\right):\left(\frac{25}{3862}\cdot\frac{1931}{25}+\frac{9}{2}\right)\)
= \(\left(\frac{1}{34}+\frac{33}{34}\right):\left(\frac{1}{2}+\frac{9}{2}\right)\)
= \(1:5\)
= \(\frac{1}{5}=0,2\)
Tính
\(\left(\left(\frac{2}{193}-\frac{3}{386}\right)-\frac{193}{17}+\frac{33}{34}\right):\left(\left(\frac{7}{1931}+\frac{11}{3862}\right).\frac{1931}{25}+\frac{9}{2}\right)\)
\(=\left(\frac{1}{386}-\frac{193}{17}+\frac{33}{34}\right):\left(\frac{25}{3862}\cdot\frac{1931}{25}+\frac{9}{2}\right)\)
\(=\left[\frac{1}{386}-\left(\frac{193}{17}-\frac{33}{34}\right)\right]:\left(\frac{1}{2}+\frac{9}{2}\right)\)
\(=\left(\frac{1}{386}-\frac{386}{34}\right)\div5\)
\(=\frac{1}{386}\cdot\frac{1}{5}-\frac{386}{34}\cdot\frac{1}{5}=\frac{1}{1930}-\frac{386}{170}=\)là 1 phân số âm.
tính.
((2/193-3/386).193/17+33/34):((7/1931+11/3862).1931/25+9/2
tìm các giá trị của x để các biểu thức
a.x mũ 2+5x
b.3(2x+3)(3x-3)
tìm giá trị của x để biểu thức nhận giá trị âm nhé
Câu tính bn vít lại đề ik, khó hỉu wa
2) a. x2 + 5x = x.(x + 5) âm
=> x.(x + 5) < 0
=> x và x + 5 trái dấu
Mà x < x + 5
=> x < 0; x + 5 > 0
=> x < 0; x > -5
=> x thuộc {-4 ; -3; -2; -1}
b. 3.(2x + 3).(3x - 3)
= 3.(2x + 3).3.(x - 1)
= 9.(2x + 3).(x - 1) âm
=> 9.(2x + 3).(x - 1) < 0
=> (2x + 3).(x - 1) < 0
=> (2x + 3).(2x - 2) < 0
Mà 2x + 3 > 2x - 2
=> 2x + 3 > 0; 2x - 2 < 0
=> 2x > -3; 2x < 2
=>x > -3/2; x < 1
=> x > -2; x < 1
=> x thuộc {-1; 0}
\(\left(\left(\frac{2}{193}-\frac{3}{386}\right).\frac{193}{17}+\frac{33}{34}\right):\left(\left(\frac{7}{1931}+\frac{11}{3862}\right).\frac{1935}{25}+\frac{9}{2}\right)\)
\(=\left(\left(\frac{4}{386}-\frac{3}{386}\right)\frac{193}{17}+\frac{33}{34}\right):\left(\left(\frac{14}{3862}+\frac{11}{3862}\right).\frac{1935}{25}+\frac{9}{2}\right)\)
\(=\left(\frac{1}{386}.\frac{193}{17}+\frac{33}{34}\right):\left(\frac{25}{3862}.\frac{1935}{25}+\frac{9}{2}\right)\)
\(=\left(\frac{1}{34}+\frac{33}{34}\right):\left(\frac{1}{2}+\frac{9}{2}\right)\)
\(=1:\frac{10}{2}=1.\frac{1}{5}=\frac{1}{5}\)
Tính
\(\left[\left(\dfrac{2}{193}-\dfrac{3}{386}\right).\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\left(\dfrac{7}{1931}+\dfrac{11}{3862}\right).\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
\(\left[\left(\dfrac{2}{193}-\dfrac{3}{386}\right).\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\left(\dfrac{7}{1931}+\dfrac{11}{3862}\right).\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
\(=\left[\left(\dfrac{4}{386}-\dfrac{3}{386}\right).\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\left(\dfrac{14}{3862}+\dfrac{11}{3862}\right).\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
\(=\left[\dfrac{1}{386}.\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\dfrac{25}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
\(=\left[\dfrac{1}{34}+\dfrac{33}{34}\right]:\left[\dfrac{1}{2}+\dfrac{9}{2}\right]\)
\(=1:5\)
\(=\dfrac{1}{5}\)
\(=0,2\)
Theo đề ta có:
\(\left[\left(\dfrac{2}{193}-\dfrac{3}{389}\right).\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\dfrac{7}{1931}+\dfrac{11}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
=> \(\left[\left(\dfrac{4}{368}-\dfrac{3}{368}\right).\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\dfrac{7}{1931}+\dfrac{11}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
=> \(\left[\dfrac{1}{386}.\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\dfrac{7}{1931}+\dfrac{11}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
=> \(\left[\dfrac{1}{2}.\dfrac{1}{17}+\dfrac{33}{34}\right]:\left[\dfrac{7}{1931}+\dfrac{11}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
=> \(\left[\dfrac{1}{34}+\dfrac{33}{34}\right]:\left[\dfrac{7}{1931}+\dfrac{11}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
=> \(\left[\dfrac{34}{34}\right]:\left[\dfrac{7}{1931}+\dfrac{11}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
=> \(1:\left[\dfrac{7}{1931}+\dfrac{11}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
=> \(1:\left[\dfrac{14}{3862}+\dfrac{11}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
=>\(1:\left[\dfrac{25}{3862}.\dfrac{1931}{25}+\dfrac{9}{2}\right]\)
=> \(1:\left[1+\dfrac{9}{2}\right]\)
=> \(1:\left[\dfrac{2}{2}+\dfrac{9}{2}\right]\)
=> \(1:\dfrac{11}{2}\)
=> \(1.\dfrac{2}{11}\)
=> \(\dfrac{2}{11}\)