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\(\frac{-8}{3}+\frac{-1}{3}\)=\(\frac{-9}{3}\)
=-3
\(\frac{-2}{7}+\frac{-1}{7}=\frac{-3}{7}< 0\)
Đề bài trở thành:-3<x<0
Vậy các số cần tìm là -2;-1
1: =-2/9(15/17+2/17)=-2/9
2: \(=\dfrac{-6}{3}+\dfrac{-21}{90}\)
=-2-7/30=-67/30
3: \(=\dfrac{3}{4}\cdot\dfrac{7}{5}+\dfrac{9}{7}\cdot\dfrac{3}{2}\)
=21/20+27/14=417/140
4: =-25/13(5/19+14/19)=-25/13
5: =-7/5-45/21=-7/5-15/7=-124/35
1: =-2/9(15/17+2/17)=-2/9
2: =−63+−2190=−63+−2190
=-2-7/30=-67/30
3: =34⋅75+97⋅32=34⋅75+97⋅32
=21/20+27/14=417/140
4: =-25/13(5/19+14/19)=-25/13
5: =-7/5-45/21=-7/5-15/7=-124/35
a, \(\Leftrightarrow2x^2=72\)
\(\Leftrightarrow x^2=36\)
\(\Leftrightarrow x=\pm6\)
Vậy ...
\(b,\Leftrightarrow\dfrac{3}{5}x-0,75=2\dfrac{4}{5}.\dfrac{3}{7}=\dfrac{6}{5}\)
\(\Leftrightarrow\dfrac{3}{5}x=\dfrac{6}{5}+0,75=\dfrac{39}{20}\)
\(\Leftrightarrow x=\dfrac{39}{20}:\dfrac{3}{5}=\dfrac{13}{4}\)
Vậy ...
\(c,\Leftrightarrow2x=1\dfrac{5}{6}.\dfrac{6}{11}-\dfrac{3}{10}=\dfrac{7}{10}\)
\(\Leftrightarrow x=\dfrac{7}{10}:2=\dfrac{7}{20}\)
Vậy ...
\(d,\Leftrightarrow\dfrac{1}{x-7\dfrac{1}{3}}=1.5:2\dfrac{1}{4}=\dfrac{2}{3}\)
\(\Leftrightarrow x-7\dfrac{1}{3}=\dfrac{3}{2}\)
\(\Leftrightarrow x=\dfrac{3}{2}+7\dfrac{1}{3}=\dfrac{53}{6}\)
Vậy ...
a) 2x2 - 72 = 0
\(\Rightarrow\) 2x2 = 72
\(\Rightarrow\) x2 = 36 = 62 = (- 6)2
\(\Rightarrow\) x = 6 hoặc x = - 6
Vậy x = 6 hoặc x = - 6
b) (\(\dfrac{3}{5}\)x - 0,75) : \(\dfrac{3}{7}\) = \(2\dfrac{4}{5}\)
\(\Rightarrow\) (\(\dfrac{3}{5}\)x - 0,75) : \(\dfrac{3}{7}\) = \(\dfrac{14}{5}\)
\(\Rightarrow\) \(\dfrac{3}{5}\)x - \(\dfrac{3}{4}\) = \(\dfrac{6}{5}\)
\(\Rightarrow\) \(\dfrac{3}{5}\)x = \(\dfrac{39}{20}\)
\(\Rightarrow\) x = \(\dfrac{13}{4}\)
Vậy x = \(\dfrac{13}{4}\)
a) 2/3 x + 1/2 = 1/10
2/3 x = 1/10 - 1/2
2/3 x = -2/5
x = -2/5 : 2/3
x = -3/5
b) 2/3 x + 1/5 = 7/10
2/3 x = 7/10 - 1/5
2/3 x = 1/2
x = 1/2 : 2/3
x = 3/4
c) (3 4/5 - 2x) . 1 1/3 = 5
19/5 - 2x = 5 : 4/3
19/5 - 2x = 15/4
2x = 19/5 - 15/4
2x = 1/20
x = 1/20 : 2
x = 1/40
d) x/7 = 6/(-21)
x = 6.7/(-21)
x = -2
Bài 1: Dễ, tính máy tính là ra
Bài 2:
a) \(\dfrac{1}{5}+1\dfrac{1}{4}x=\dfrac{2}{3}\)
\(\Rightarrow1\dfrac{1}{4}x=\dfrac{7}{15}\Rightarrow x=\dfrac{28}{75}\)
Vậy \(x=\dfrac{28}{75}\)
b) \(\left(\dfrac{2}{7}x-1\dfrac{1}{2}x\right):\dfrac{2}{7}=\dfrac{-21}{4}\)
\(\Rightarrow\left(\dfrac{2}{7}x-\dfrac{3}{2}x\right):\dfrac{2}{7}=\dfrac{-21}{4}\)
\(\Rightarrow\dfrac{2}{7}x-\dfrac{3}{2}x=\dfrac{-3}{2}\)
\(\Rightarrow x\left(\dfrac{2}{7}-\dfrac{3}{2}\right)=\dfrac{-3}{2}\)
\(\Rightarrow\dfrac{-17}{14}x=\dfrac{-3}{2}\Rightarrow x=\dfrac{21}{17}\)
Vậy \(x=\dfrac{21}{17}\)
c) \(\dfrac{5}{8}+\dfrac{1}{3}:x=\dfrac{1}{2}\)
\(\Rightarrow\dfrac{1}{3}:x=\dfrac{-1}{8}\Rightarrow x=\dfrac{-8}{3}\)
Vậy \(x=\dfrac{-8}{3}\)
d) \(\dfrac{-5}{6}+\dfrac{8}{3}+\dfrac{-29}{6}< x< \dfrac{-1}{2}+2+\dfrac{5}{2}\)
\(\Rightarrow-3< x< 4\)
\(\Rightarrow x\in\left\{-2;-1;0;1;2;3\right\}\) vì x thuộc Z
Vậy \(\Rightarrow x\in\left\{-2;-1;0;1;2;3\right\}\)
Các bạn ơi giúp mk trả lời mấy câu hỏi này với mk đang cần rất gấp ngay bây giờ đây nè!!!!!
2:
a: x+201=351
=>x=351-201
=>x=150
b: \(8\cdot5^2-27:25\)
\(=8\cdot25-\dfrac{27}{25}\)
\(=200-1,08=198,92\)
d: \(2023-23:\left[9+2\left(2^3-0,21\right)\right]\)
\(=2023-23:\left[9+16-0,42\right]\)
\(=2023-\dfrac{23}{25-0,42}\)
\(=2023-\dfrac{1150}{1229}=\dfrac{2485117}{1229}\)
b: 2(x-21)=84
=>x-21=84/2=42
=>x=42+21=63
c: 135-4(81-x)=55
=>4(81-x)=135-55=80
=>81-x=20
=>x=61
a: \(=\dfrac{3}{5}:\dfrac{7}{5}=\dfrac{3}{5}\cdot\dfrac{5}{7}=\dfrac{3}{7}\)
b: \(=\dfrac{9}{17}\left(\dfrac{8}{5}-\dfrac{3}{5}\right)+\dfrac{8}{17}\)
=9/17+8/17=1
c: =>x-3/10=7/15*1/5=7/75
=>x=7/75+3/10=59/150
làm hộ tui nhanh nha ❤