a. 2/7-2/7 . 7/12
b. -11/12. 18/25+ -11/12.7/25+5/12
c. x- 3/5= 2/3
d. [ x- 1/3] ; 1/2 + 3/7 = 5 và 3/7
e. -2/3x + 1/5x = -14/15
giúp mình với mình đang cần gấp!
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a) -7/25 . 11/13 + -7/25 . 2/13 - 18/25=-1
b) 5/7 . 1/3 - 5/7 . 1/4 - 5/7 . 1/12=0
c) 5 + 2/5 . 4+ 2/7 + 5 + 5/7 . 5+ 2/5=18
d) 75% - 3/2 + 0,5 - [ -1/2]^2=-1/2
a, 2.x + 7 = 15
2x = 8
x = 4
b, 25 – 3.(6 – x) = 22
3.(6-x) = 3
6-x = 1
x = 5
c, [(2x – 11) : 3 + 1].5 = 20
(2x-11) : 3+1 = 4
(2x-11):3 = 3
2x-11 = 1
2x = 12
x = 6
e, 2 . 3x = 10 . 312 + 8 . 274
6x = 3120 + 2192
6x = 5312
x = 5312/6
g, x – 12 = (–8) + (–17)
x - 12 = -25
x = -13
Lần sau tách nhỏ nội dung câu hỏi ra nha em, chứ trả lời thế này biếng lắm '^^ Chị làm chỉ mang tính tham khảo kết quả thôi, còn cụ thể thì em tách từng bước một ra he :>
a, \(2\cdot x+7=15\)
\(\Leftrightarrow2\cdot x=8\)
\(\Leftrightarrow x=4\)
Vậy x = 4.
b, \(25-3\cdot\left(6-x\right)=22\)
\(\Leftrightarrow3\cdot\left(6-x\right)=3\)
\(\Leftrightarrow6-x=1\)
\(\Leftrightarrow x=5\)
Vậy x = 5.
c, \(\left[\left(2x-11\right):3+1\right]\cdot5=20\)
\(\Leftrightarrow\left(2x-11\right):3+1=4\)
\(\Leftrightarrow\left(2x-11\right):3=3\)
\(\Leftrightarrow2x-11=9\)
\(\Leftrightarrow2x=20\)
\(\Leftrightarrow x=10\)
Vậy x = 10.
d, \(\left(25-2x\right)\cdot3:5-32=42\)
\(\Leftrightarrow\)\(\frac{3\cdot\left(25-2x\right)}{5}=74\)
\(\Leftrightarrow3\cdot\left(25-2x\right)=370\)
\(\Leftrightarrow25-2x=\frac{370}{3}\)
\(\Leftrightarrow2x=-\frac{295}{3}\)
\(\Leftrightarrow x\approx49\)
Vậy \(x\approx49\) .
e, \(2\cdot3x=10\cdot312+8\cdot274\)
\(\Leftrightarrow6x=5312\)
\(\Leftrightarrow x=5312:6\approx885\)
Vậy \(x\approx885\) .
g, \(x-12=\left(-8\right)+\left(-17\right)\)
\(\Leftrightarrow x-12=-25\)
\(\Leftrightarrow x=-25+12=-13\)
Vậy x = -13.
h, \(7-2x=18-3x\)
\(\Leftrightarrow-2x+3x=18-7\)
\(\Leftrightarrow x=11\)
Vậy \(x=11\) .
i, \(3\cdot\left(x+5\right)-x-11=24\)
\(\Leftrightarrow3x+15-x-11=24\)
\(\Leftrightarrow2x=24+11-15\)
\(\Leftrightarrow2x=20\)
\(\Leftrightarrow x=10\)
Vậy \(x=10\) .
giúp mình bài này với
bạn nam đọc 1 quyển sách trong 3 ngày . ngày 1 đọc 1 phần 3 số trang . ngày thứ 2 đọc 2 phần 5 số trang còn lại .ngày 3 đọc 36 trang còn lại. hỏi quyển sách có bao nhiêu trang
`Answer:`
a. \(-\frac{17}{30}-\frac{11}{-15}+-\frac{7}{12}\)
\(=-\frac{17}{30}+\frac{11}{15}-\frac{7}{12}\)
\(=-\frac{17}{30}+\frac{22}{30}-\frac{7}{12}\)
\(=\frac{1}{6}-\frac{7}{12}\)
\(=-\frac{5}{12}\)
b. \(-\frac{5}{9}+\frac{5}{9}:\left(\frac{5}{3}-\frac{25}{12}\right)\)
\(=-\frac{5}{9}+\frac{5}{9}:\left(-\frac{5}{12}\right)\)
\(=\frac{5}{9}.\left(-1\right)+\frac{5}{9}.\left(-\frac{12}{5}\right)\)
\(=\frac{5}{9}.\left(-1-\frac{12}{5}\right)\)
\(=\frac{5}{9}.\frac{-17}{5}\)
\(=-\frac{17}{9}\)
c. \(-\frac{7}{25}.\frac{11}{13}+-\frac{7}{25}-\frac{2}{13}-\frac{18}{25}\)
\(=\frac{77}{325}-\left(\frac{7}{25}+\frac{18}{25}\right)-\frac{2}{13}\)
\(=\frac{77}{325}-1-\frac{2}{13}\)
\(=-\frac{452}{325}\)
a. -3/4 x 12/-5 x (-25/6)=-15/2
b. -2 x -38/21 x -7/4 x (-3/8)=-19/8
c. (11/12: 33/16) x 3/5=4/15
d. 7/23 x [(-8/6)- 45/18]=-7/6
\(\dfrac{1}{2}+\dfrac{3}{4}-\left(\dfrac{3}{4}-\dfrac{4}{5}\right)\)
=\(\dfrac{1}{2}+\dfrac{3}{4}-\dfrac{3}{4}+\dfrac{4}{5}\)
=\(\left(\dfrac{1}{2}+\dfrac{4}{5}\right)+\left(\dfrac{3}{4}-\dfrac{3}{4}\right)\)
=\(\left(\dfrac{5}{10}+\dfrac{8}{10}\right)+0\)
=\(\dfrac{13}{10}\)
\(-\dfrac{7}{25}.\dfrac{11}{13}+\left(-\dfrac{7}{25}\right).\dfrac{2}{13}-\dfrac{18}{25}\)
=\(-\dfrac{7}{25}.\cdot\left(\dfrac{11}{13}+\dfrac{2}{13}\right)-\dfrac{18}{25}\)
=\(-\dfrac{7}{25}.1-\dfrac{18}{25}\)
=\(-\dfrac{7}{25}-\dfrac{18}{25}\)
=\(-\dfrac{25}{25}\) = \(-1\)
\(a.\dfrac{2}{3}+\dfrac{1}{5}\cdot\dfrac{10}{7}\\ =\dfrac{2}{3}+\dfrac{2}{7}=\dfrac{20}{21}\\ b.\dfrac{7}{12}-\dfrac{27}{7}\cdot\dfrac{1}{18}\\ =\dfrac{7}{12}-\dfrac{3}{14}=\dfrac{31}{84}\\ c.\left(\dfrac{23}{11}-\dfrac{15}{82}\right)\cdot\dfrac{41}{25}\\ =\dfrac{1721}{902}\cdot\dfrac{41}{25}=\dfrac{1721}{550}\\ d.\left(\dfrac{4}{5}+\dfrac{1}{2}\right)\cdot\left(\dfrac{3}{13}-\dfrac{8}{13}\right)\\ =\dfrac{13}{10}\cdot\left(\dfrac{-5}{13}\right)=\dfrac{-1}{2}\)
a. \(x-\dfrac{2}{35}=\dfrac{-2}{25}\)
<=> \(x=\dfrac{-2}{25}+\dfrac{2}{35}\)
<=> x = \(-\dfrac{4}{175}\)
b. \(\dfrac{11}{12}-\left(x+\dfrac{2}{5}\right)=\dfrac{2}{3}\)
<=> \(\dfrac{11}{12}-x-\dfrac{2}{5}=\dfrac{2}{3}\)
<=> \(-x=\dfrac{2}{3}-\dfrac{11}{12}+\dfrac{2}{5}\)
<=> \(-x=\dfrac{3}{20}\)
<=> \(x=\dfrac{-3}{20}\)
c. \(\dfrac{2}{5}+\dfrac{1}{4}x=\dfrac{-3}{10}\)
<=> \(\dfrac{1}{4}x=\dfrac{-3}{10}-\dfrac{2}{5}\)
<=> \(\dfrac{1}{4}x=\dfrac{-7}{10}\)
<=> \(x=\dfrac{-14}{5}\)
a) \(x-\dfrac{2}{35}=-\dfrac{2}{25}\)
\(\Rightarrow x=-\dfrac{2}{25}+\dfrac{2}{35}\)
\(\Rightarrow x=-\dfrac{4}{175}\)
b) \(\dfrac{11}{12}-\left(x+\dfrac{2}{5}\right)=\dfrac{2}{3}\)
\(\Rightarrow x+\dfrac{2}{5}=\dfrac{11}{12}-\dfrac{2}{3}\)
\(\Rightarrow x+\dfrac{2}{5}=\dfrac{1}{4}\)
\(\Rightarrow x=\dfrac{1}{4}-\dfrac{2}{5}\)
\(\Rightarrow x=-\dfrac{3}{20}\)
c) \(\dfrac{2}{5}+\dfrac{1}{4}x=-\dfrac{3}{10}\)
\(\Rightarrow\dfrac{1}{4}x=-\dfrac{3}{10}-\dfrac{2}{5}\)
\(\Rightarrow\dfrac{1}{4}x=-\dfrac{7}{10}\)
\(\Rightarrow x=-\dfrac{7}{10}:\dfrac{1}{4}\)
\(\Rightarrow x=-\dfrac{14}{5}\)
a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)
\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)
\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)
b) \(\dfrac{39}{7}:x=13\)
\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)
c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)
\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)
\(\dfrac{14}{5}x=34+50=84\)
\(x=\dfrac{84}{\dfrac{14}{5}}=30\)
d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)
e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)
\(\dfrac{1}{6}x=\dfrac{5}{12}\)
\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)
g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)
\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)
\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)
\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)
\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)
h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)
\(x=1\)
Mỏi tay woa bn làm nốt nha!!
a) \(\dfrac{2}{7}-\dfrac{2}{7}\times\dfrac{7}{12}\)
= \(\dfrac{2}{7}-\dfrac{1}{6}\)
= \(\dfrac{5}{42}\)
b) \(\dfrac{-11}{12}\times\dfrac{18}{25}+\dfrac{-11}{12}\times\dfrac{7}{25}+\dfrac{5}{12}\)
= \(\dfrac{-11}{12}\times\left(\dfrac{18}{25}+\dfrac{7}{25}\right)+\dfrac{5}{12}\)
= \(\dfrac{-11}{12}\times1+\dfrac{5}{12}\)
= \(\dfrac{-11}{12}+\dfrac{5}{12}\)
= \(\dfrac{-1}{2}\)
c) \(\left(x-\dfrac{1}{3}\right)\div\dfrac{1}{2}+\dfrac{3}{7}=5\dfrac{3}{7}\)
\(\left(x-\dfrac{1}{3}\right)\times2+\dfrac{3}{7}=5\dfrac{3}{7}\)
\(\left(x-\dfrac{1}{3}\right)\times2=5\dfrac{3}{7}-\dfrac{3}{7}\)
= \(\left(x-\dfrac{1}{3}\right)\times2=5\)
\(x-\dfrac{1}{3}=5\div2\)
\(x-\dfrac{1}{3}=\dfrac{5}{2}\)
\(x=\dfrac{5}{2}+\dfrac{1}{3}\)
\(x=\dfrac{17}{6}\)
Vậy \(x=\dfrac{17}{6}\)
e) \(\dfrac{-2}{3}x+\dfrac{1}{5}x=\dfrac{-14}{15}\)
\(x\left(\dfrac{-2}{3}+\dfrac{1}{5}\right)=\dfrac{-14}{15}\)
\(x\times\dfrac{-7}{15}=\dfrac{-14}{15}\)
\(x=\dfrac{-14}{15}:\dfrac{-7}{15}\)
\(x=2\)
Vậy \(x=2\)