7/9 . 8/11 + 7/9 . 3/11 - 45/19 =...........................
1,4.15/49 - (20%+2/3):11/5=.....................
-7/6 - x=1/6
30%x=-6/5
4/3-(0,5+2/3x)=1/6
một thùng có chứa 240 lít dầu. lần thứ nhất người ta lấy ra 1/3 tổng số lít dầu, lần thứ 2 người ta lấy ra 40% SỐ DẦU CÒN lại.Hỏi trong thùng còn bao nhiêu lít
giúp mk với mk cần gấp sáng nay nha
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1) \(\left(+15\right)+\left(+17\right)=15+17=32\)
2) \(\left(-3\right)+\left(-7\right)=-3-7=-\left(3+7\right)=-10\)
3) \(\left(-25\right)+\left(+4\right)=-25+4=-\left(25-4\right)=-21\)
4) \(\left(-6\right)+\left(-54\right)=-6-54=-\left(6+54\right)=-60\)
5) \(\left(-15\right)+20=20-15=5\)
6) \(\left(-5\right)+8+7+5\)
\(=\left(-5+5\right)+\left(8+7\right)\)
\(=15\)
7) \(\left(-8\right)+\left(-11\right)+\left(-2\right)\)
\(=\left[\left(-8\right)+\left(-2\right)\right]+\left(-11\right)\)
\(=\left(-10\right)+\left(-11\right)\)
\(=-21\)
8) \(15+\left(-5\right)+\left(-14\right)+\left(-16\right)\)
\(=\left[15+\left(-5\right)\right]+\left[\left(-14\right)+\left(-16\right)\right]\)
\(=10+\left(-30\right)\)
\(=-20\)
9) \(\left(-20\right)+\left(-14\right)+3+\left(-86\right)\)
\(=\left[\left(-20\right)+3\right]+\left[\left(-14\right)+\left(-86\right)\right]\)
\(=\left(-17\right)+\left(-100\right)\)
\(=-117\)
10) \(\left(-136\right)+123+\left(-264\right)+\left(-83\right)+240\)
\(=\left[\left(-136\right)+\left(-264\right)\right]+\left[123+\left(-83\right)\right]+240\)
\(=\left(-400\right)+40+240\)
\(=\left(-360\right)+240\)
\(=-120\)
11) \(\left(-596\right)+2001+1999+\left(-404+189\right)\)
\(=\left(-596\right)+2001+1999-404+189\)
\(=\left[\left(-596\right)-404\right]+\left(2001+189\right)+1999\)
\(=\left(-1000\right)+2190+1999\)
\(=1190+1999\)
\(=3189\)
12) \(314+\left(-153\right)+64+121+\left(-247\right)+218\)
\(=\left(314+64+121\right)+\left[\left(-153\right)+\left(-247\right)\right]+218\)
\(=\left(378+121\right)+\left(-400\right)+218\)
\(=499-400+218\)
\(=99+218\)
\(=317\)
\(\text{#}Toru\)
2: \(=\dfrac{-2}{75}+\dfrac{5}{39}=\dfrac{33}{325}\)
3: \(=\dfrac{6}{11}\left(\dfrac{4}{9}+\dfrac{5}{9}\right)=\dfrac{6}{11}\)
4: \(=\dfrac{7}{19}\left(\dfrac{5}{13}+\dfrac{8}{13}-1\right)=-2\cdot\dfrac{7}{19}=-\dfrac{14}{19}\)
5: \(=\dfrac{2}{7}\left(\dfrac{4}{23}-\dfrac{27}{23}+1\right)=0\)
6: \(=\dfrac{3}{8}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\dfrac{11}{8}=\dfrac{3}{8}+\dfrac{11}{8}=\dfrac{14}{8}=\dfrac{7}{4}\)
20) -5-(x + 3) = 2 - 5x ⇔ -5 - x - 3 = 2 -5x ⇔ 4x = 10 ⇔ x = \(\frac{5}{2}\)
Vậy...
Lần thứ nhất người ta lấy số lít dầu là:
60x4/15 = 16 (lít)
Lần thứ 2 người ta lấy số lít dầu là:
(60-16)x6/11=24 (lít)
Sau 3 lần lấy thì trong thùng còn số lít dầu là:
60-(16+24+12)=8 (lít)
Đáp số: 8 lít dầu
Ai k mik mik k lại
`4/7+4`
`=4/7+4/1`
`=4/7+28/7`
`=32/7`
__
`3+6/11`
`=33/11+6/11`
`=39/11`
__
`3-5/7`
`=3/1-5/7`
`=21/7-5/7`
`=16/7`
__
`21/9-2`
`=21/9-18/9`
`=3/9`
`=1/3`
__
`15/24+2`
`=15/24+48/24`
`=63/24`
`=21/16`
__
`63/45-20/25`
`=63/45-4/5`
`=63/45-36/45`
`=27/45`
`=9/15`
__
`3/4-2/8`
`=3/4-1/4`
`=2/4`
__
`6/7-5/8`
`=48/56-35/56`
`=13/56`
__
`37/45-5/9`
`=37/45-25/45`
`=12/45`
`=4/15`
__
`46/39-11/13`
`=46/39-33/39`
`=13/39`
`=1/2`
__
`5/12+3/4+1/3`
`=5/12+9/12+4/12`
`=14/12+4/12`
`=18/12`
`=3/2`
__
`1/2+3/7+11/14`
`=7/14+6/14+11/14`
`=13/14+11/14`
`=24/14`
`=12/7`
__
`7/10-(1/5+1/4)`
`=7/10-(4/20+5/20)`
`=7/10-9/20`
`=14/20-9/20`
`=5/20`
`=1/4`
__
`15/4-2/3-3/4`
`=(15/4-3/4)-2/3`
`=12/4-2/3`
`=3-2/3`
`=9/3-2/3`
`=7/3`
nhầm
\(\frac{5}{11}+\frac{19}{25}+\frac{6}{11}+\frac{11}{16}+\frac{6}{25}+\frac{5}{16}\)
\(=\left(\frac{5}{11}+\frac{6}{11}\right)+\left(\frac{19}{25}+\frac{6}{25}\right)+\left(\frac{11}{16}+\frac{5}{16}\right)\)
=1+1+1
=3
1: =72/90+65/90=137/90
2: =24/56-77/56=-53/56
3: =-7/10+4/5=1/10
4: =15/100-4/100=11/100
5: =4/6-5/6=-1/6
6: =10/40-15/40-76/40=-81/40
7: =-9/10+7/18
=-81/90+35/90=-46/90=-23/45
8: =27/90-55/90=-28/90=-14/45
9: =36/60-50/60-35/60=-49/60
10: =-4/9+5/6-3/8
=-32/72+60/72-27/72
=1/72
\(\frac{-7}{12}+\frac{11}{8}-\frac{5}{9}\)
\(=\frac{-42}{72}+\frac{99}{72}+\frac{-40}{72}\)
\(=\frac{17}{72}\)
\(\frac{7}{9}\cdot\frac{8}{11}+\frac{7}{9}\cdot\frac{3}{11}-\frac{45}{19}\)
\(=\frac{7}{9}\left[\frac{8}{11}+\frac{3}{11}\right]-\frac{45}{19}\)
\(=\frac{7}{9}\cdot1-\frac{45}{19}=-\frac{272}{171}\)
\(1,4\cdot\frac{15}{49}-\left[20\%+\frac{2}{3}\right]:\frac{11}{5}\)
\(=\frac{14}{10}\cdot\frac{15}{49}-\left[\frac{20}{100}+\frac{2}{3}\right]\cdot\frac{5}{11}\)
\(=\frac{7}{5}\cdot\frac{15}{49}-\left[\frac{1}{5}+\frac{2}{3}\right]\cdot\frac{5}{11}\)
\(=\frac{1}{1}\cdot\frac{3}{7}-\frac{13}{15}\cdot\frac{5}{11}\)
\(=\frac{3}{7}-\frac{13}{3}\cdot\frac{1}{11}\)
\(=\frac{3}{7}-\frac{13}{33}=\frac{8}{231}\)
\(-\frac{7}{6}-x=\frac{1}{6}\)
\(\Rightarrow x=-\frac{7}{6}-\frac{1}{6}\)
\(\Rightarrow x=-\frac{4}{3}\)
\(30\%x=-\frac{6}{5}\)
\(\Rightarrow\frac{30}{100}x=-\frac{6}{5}\)
\(\Rightarrow\frac{3}{10}x=-\frac{6}{5}\Leftrightarrow x=-4\)
Làm nốt hai bài còn lại