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\(\left(7\dfrac{4}{9}+4\dfrac{7}{11}\right)-3\dfrac{4}{9}\)
\(=\dfrac{67}{9}+\dfrac{51}{11}-\dfrac{31}{9}\)
\(=\dfrac{67}{9}-\dfrac{31}{9}+\dfrac{51}{11}\)
\(=4+\dfrac{51}{11}\)
\(=\dfrac{95}{11}\)
Chúc bạn học tốt
a) \(\dfrac{-15}{4}:\dfrac{21}{-10}=\dfrac{-15}{4}.\dfrac{-10}{21}=\dfrac{25}{14}\)
b) \(\dfrac{-7}{14}:\left(-0,14\right)=\dfrac{-7}{14}.\dfrac{-50}{7}=\dfrac{25}{7}\)
c) \(\left(\dfrac{-11}{15}\right):1\dfrac{1}{10}=\dfrac{-11}{15}.\dfrac{10}{11}=\dfrac{-2}{3}\)
d) \(2\dfrac{1}{7}:1\dfrac{1}{14}=\dfrac{15}{7}.\dfrac{14}{15}=2\)
\(a.-\dfrac{15}{4}:\left(\dfrac{21}{-10}\right)\)
\(=-\dfrac{15}{4}\cdot\left(-\dfrac{10}{21}\right)\)
\(=\dfrac{25}{14}\)
\(b.-\dfrac{7}{14}:\left(-0,14\right)\)
\(=-\dfrac{1}{2}:\left(-\dfrac{7}{50}\right)\)
\(=\dfrac{25}{7}\)
\(c.\left(-\dfrac{11}{15}\right):\left(1\dfrac{1}{10}\right)\)
\(=\left(-\dfrac{11}{15}\right):\dfrac{11}{10}\)
\(=-\dfrac{2}{3}\)
\(d.\left(2\dfrac{1}{7}\right):\left(1\dfrac{1}{14}\right)\)
\(=\dfrac{15}{7}:\dfrac{15}{14}\)
\(=2\)
TL
\(\frac{3}{4}+\frac{2}{3}=\frac{17}{12}\)
\(\frac{4}{5}+\frac{1}{2}-\frac{7}{10}=\frac{3}{5}\)
\(\frac{7}{6}\).\(\frac{1}{3}+\frac{7}{6}\).\(\frac{1}{2}\)-\(\frac{7}{6}\) . \(\frac{5}{8}\)=\(\frac{7}{6}.\)(\(\frac{1}{3}+\frac{1}{2}-\frac{5}{8}\))=\(\frac{7}{6}.\)\(\frac{5}{24}\)=\(\frac{35}{144}\)
HT
\(C=5\frac{9}{10}:\frac{3}{2}-\left(2\frac{1}{3}.4\frac{1}{2}-2.2\frac{1}{3}\right):\frac{7}{4}\)
\(=\frac{59}{10}:\frac{3}{2}-\left(\frac{7}{3}.\frac{9}{2}-2.\frac{7}{3}\right):\frac{7}{4}\)
\(=\frac{59}{15}-\left[\frac{7}{3}\left(\frac{9}{2}-2\right)\right]:\frac{7}{4}\)
\(=\frac{59}{15}-\frac{35}{6}:\frac{7}{4}\)
\(=\frac{59}{15}-\frac{10}{3}\)
\(=\frac{9}{15}=\frac{3}{5}\)
\(\cdot62,87+35,14+4,13+8,35+4,86+5,65\)
\(=\left(62,87+4,13\right)+\left(35,14+4,86\right)+\left(8,35+5,65\right)\)
\(=67+40+14\)
\(=121\)
1)(x+1)thuộc ước của -2
ư(2)={1;2;-1;-2}
x+1 | 1 | 2 | -1 | -2 |
x | 0 | 1 | -2 | -3 |
vậy x =0;x=1;x=-2;x=-3
2)ta có : 2x+7=2(x+3)+1
2(x+3)chia hết cho x+3
=>để 2x+7chia hết cho x+3
<=>1chia hết cho x+3
=>x+3 thuộc ư(1)
u(1)={1;-1}
x+3 | 1 | -1 |
2 | -2 | -4 |
vậy x=-2;x=-4
đề là gì ?
tìm S hay tìm 5S
???
nếu tìm S
S5=1+4+7+...+79
=>5S=(79+1)[(79-1):3+1]:2
=>5S=80[78:3+1]:2
=>5S=80.27:2
=>5S=1080
=>S=216