\(D=\left(19\dfrac{5}{8}:\dfrac{7}{12}-13\dfrac{1}{4}:\dfrac{7}{12}\right)\cdot\dfrac{4}{5}\)
\(=\left(\dfrac{157}{8}\cdot\dfrac{12}{7}-\dfrac{53}{4}\cdot\dfrac{12}{7}\right)\cdot\dfrac{4}{5}\)
\(=\dfrac{12}{7}\left(\dfrac{157}{8}-\dfrac{53}{4}\right)\cdot\dfrac{4}{5}\\ =\dfrac{12}{7}\cdot\dfrac{51}{8}\cdot\dfrac{4}{5}\\ =\dfrac{306}{35}\)
1 . tính bằng cách hợp lí :
a . ( 5/6 + 3/4 - 0,9 ) : ( 5/6 - 3/4 + 0,9 )
b . ( 13 7/12 + 4 3/10 ) - 8 7/12
c . 31 4/17 - 8 5/13 - 11 8/13
Bài 2: Thực hiện phép tính một cách hợp lí
f) \(\dfrac{7}{19}\) . \(\dfrac{8}{11}\) + \(\dfrac{3}{11}\) . \(\dfrac{7}{19}\) +\(\dfrac{-12}{19}\)
i) ( \(\dfrac{3}{8}\) + \(\dfrac{-3}{4}\)+ \(\dfrac{7}{12}\) ) : \(\dfrac{5}{6}\) +\(\dfrac{1}{2}\)
x=1/4+2/13
x/3=2/3+-1/7
-8/3+1/3<x<-2/7+-5/7
-5/6 +8/3+29/-6=<x>=-1/2+2+5/2
1/6+2/5
3/5+-7/4
4/13+-12/30
-3/29+16/58
8/40+-36/45
-8/18+15/27
a, \(\left(12-\frac{7}{18}-10\frac{13}{18}\right):x-1\frac{7}{13}=1\frac{2}{3}\)
b,\(\left[\left(6\frac{3}{7}-\frac{0,75x-2}{0,35}\right).2,8+1,75\right]:0,05=235\)
c.\(\frac{3-x}{5-x}=\left(\frac{3}{5}\right)^2\)
d,\(\left(1-\frac{3}{10}-x\right):\left(\frac{19}{10}-1-\frac{2}{5}\right)+\frac{4}{5}=1\)
e,\(\left(12\frac{7}{18}-10\frac{13}{18}\right):x-1\frac{7}{33}:\frac{8}{11}=1\frac{2}{3}\)
các bạn ơi giúp tớ với
\(a.19\dfrac{5}{8}:\dfrac{7}{12}-15\dfrac{1}{4}:\dfrac{7}{12} b.\dfrac{2}{5}.\dfrac{1}{3}-\dfrac{2}{15}:\dfrac{1}{5}+\dfrac{3}{5}.\dfrac{1}{3}\)
c.\(\left(3\dfrac{1}{3}+2,5\right):\left(3\dfrac{1}{6}-\left(4\dfrac{1}{5}\right)\right)-\dfrac{11}{31}\)
1.Tính giái trị biểu thức
c) 4/9*(5/7+2/5)-4/9*(-2/7+7/5) /////////d) (67/111+2/33-15/117)*(1/3-1/4-1/12) Giúp mk vs ạ
Tính:
A=[(5+2/5).(7+7/12)].[(13+8/9).(7+5/13)]
Tìm x
a)3/4 : x - 17/5 = 7/10
b) 2/7 + 5/7x =8/21
c)11/5 - 6/5 : x = 4/7
d) -3/4x + 3/4 =11/12
Bài 1:Thực hiện phép tính (tính hợp lý nếu có thể)
1) \(\dfrac{8}{31}\) +\(\dfrac{-12}{25}\) +\(\dfrac{23}{31}\) +\(\dfrac{-13}{25}\)
2) \(\dfrac{1}{2}\) + \(\dfrac{3}{4}\) - ( \(\dfrac{3}{4}\) - \(\dfrac{4}{5}\) )
3) \(\dfrac{7}{3}\) . \(\dfrac{-5}{2}\) . \(\dfrac{15}{21}\) .\(\dfrac{4}{-5}\)
4)\(\dfrac{1}{4}\) + \(\dfrac{3}{4}\) : ( \(-\dfrac{6}{7}\) )
5) (\(\dfrac{3}{29}\) - \(\dfrac{1}{5}\) ) . \(\dfrac{29}{3}\)
6) \(\dfrac{5}{7}\) . \(\dfrac{5}{11}\) + \(\dfrac{5}{7}\) . \(\dfrac{2}{11}\) - \(\dfrac{5}{7}\) .\(\dfrac{14}{11}\)
7)\(\dfrac{-11}{12}\) . \(\dfrac{1}{8}\) + \(\dfrac{11}{12}\) .\(\dfrac{-3}{16}\) -\(\dfrac{11}{12}\)
8) \(\dfrac{7}{4}\) . \(\dfrac{29}{5}\) -\(\dfrac{7}{9}\) .\(\dfrac{9}{4}\) +\(3\dfrac{2}{13}\)
giúp em