1 / 1 x 3 + 2 / 3 x 7 + 1 / 7 x 9 + 3 / 9 x 15 + 6 / 15 x 27
1. -2/9 x 15/17 + -2/9 x 2/17
2. -5/3 x 6/5 + -7/9 x 3/10
3. 15/20 x 7/5 + -9/7 x -6/4
4.-25/13 x 5/19 + -25/13 x 14/19
5 -7/13 x 13/5 + -9/7 x 5/3
6. 27/35 x 5/9 - 2/7 x -7/5
7. 10/13 x 13/5 + {-9/5} x 10/3
8. 100/27 x 9/20 + 40% x 5/3
9. 1,5 x 5/12 + 1/4 x 3/4
10. 2 1/2 x 7/5 + {-9/10} x 2/3
11. X + 45% = 2 1/2 -5/3
12. 80% + X = -5/2 + 3/4
13. 4/25 - X =-5/2 + -3/10
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: =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
Tính nhanh: LƯU Ý tất cả số dưới đây đều là phân số
1,1/8 x 2/5 + 3/5 + 1/8
2,( -1)/15 x 2/5 + (-5)/3 x (-1)/13
3,4/9 : 11/6 + 5/9 x 6/11
4,5/19 x 7/13 + 7/19 x 8/13 - 3 x 7/19
5, 2/7 x 4/23 - 2/7 x 27/23 + 2/7
6,3/8 x 3/7 +3/8 x 4/7 + 11/8
7,-5/27 : 6/11 - 16/11 x 5/27 - 5/27
8, 5/16 x 7/8 - 5/16 x 1/8 + 10/8 :16/5
9,1/3 x 39/17 - 129/3 x 1/17
10,5/2 : 23/3 - 3/2 x 7/23
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: \(=\dfrac{3}{8}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\dfrac{11}{8}=\dfrac{3}{8}+\dfrac{11}{8}=\dfrac{14}{8}=\dfrac{7}{4}\)
Tính:
a) 2^5 x 13^12 x 7^8 : 27 x 13^10 x 7^9
b) 2^n x 11 x 3 : 6^n x 3
c) 5^5 x 7 x 9^5 : 15^10
d) 7 x 8^10 x 27^9 - 8 x 9^13 x 2^27 : 7 x 6^26 x 2^2 - 2^4 x 8^3 x 27^9
e) 2^2^1^2015
f) 2015^0^2015^0^2015
Bài 1: Tìm x
a, x + 15/16 + 7/8 = 15/4 b, x - 27/28 - 9/14 = 13/7
c, x nhân 1/5 + x + 1/6 = 2/3 d, x: 14 = 1/4 + 2/9 + 3/4
a)\(x+\frac{15}{16}+\frac{7}{8}=\frac{15}{4}\)
\(x+\frac{29}{16}=\frac{15}{4}\)
\(x=\frac{15}{4}-\frac{29}{16}\)
\(x=\frac{31}{16}\)
b)\(x-\frac{27}{28}-\frac{9}{14}=\frac{13}{7}\)
\(x-\frac{45}{28}=\frac{13}{7}\)
\(x=\frac{13}{7}+\frac{45}{28}\)
\(x=\frac{97}{28}\)
c)\(x\times\frac{1}{5}+x+\frac{1}{6}=\frac{2}{3}\)
\(x\times\frac{1}{5}+x=\frac{2}{3}-\frac{1}{6}\)
\(x\times\left(\frac{1}{5}+1\right)=\frac{1}{2}\)
\(x\times\frac{6}{5}=\frac{1}{2}\)
\(x=\frac{1}{2}:\frac{6}{5}\)
\(x=\frac{5}{12}\)
d)\(x:14=\frac{1}{4}+\frac{2}{9}+\frac{3}{4}\)
\(x:14=\frac{11}{9}\)
\(x=\frac{11}{9}\times14\)
\(x=\frac{154}{9}\)
#H
a,
x-2/3-2/15-2/35-2/63=1/9
b
(x+1
3)+(x+1/9)+(x+1/27)+(x+1/81)=56/81
c,
(1/3*5+1/5*7+1/7*9+.....+1/19*21)*x=9/7
d,3+5+7+...+2015/2+4+6+...+2016+x=1
e,2/6+2/12+2/20+...+2/x*(x+1)=2013/2015
1. -2/9 x 15/17 + -2/9 x 2/17
2. -5/3 x 6/5 + -7/9 x 3/10
3. 15/20 x 7/5 + -9/7 x -6/4
4.-25/13 x 5/19 + -25/13 x 14/19
5 -7/13 x 13/5 + -9/7 x 5/3
`1, -2/9 xx 15/17 + (-2/9) xx 2/17`
`= -2/9 xx (15/17 + 2/17)`
`= -2/9 xx 17/17`
`=-2/9xx1`
`=-2/9`
__
`-5/3 xx 6/5 + (-7/9) xx 3/10`
`= -30/15 + (-21/90)`
`= -2 + (-7/30)`
`=-60/30 +(-7/30)`
`=-67/30`
__
`15/20 xx 7/5 + (-9/7) xx (-6/4)`
`=3/4 xx7/5 + (-9/7) xx(-6/4)`
`= 21/20 + 54/28`
`= 21/20 + 27/14`
`=417/140`
__
`-25/13 xx 5/19 + (-25/13) xx 14/19`
`=-25/13 xx (5/19 +14/19)`
`=-25/13 xx 19/19`
`= -25/13 xx 1`
`=-25/13`
__
`-7/13 xx 13/5 + (-9/7) xx 5/3`
`=-7/5 +(-15/7)`
`=-124/35`
tìm x biết
1) x=-1/2 + 3/4 2) x - 1/5 = 2/11 3) x - 5/6 = 16/42 + -8/56
4) x/5 = 5/6 + -19/30 5) |x| - 1/4 = 6/18 6)x = -1/2 +3/4
7) x/15 = 3/5 + -2/3 8)11/8 + 13/6 = 85/x 9) x - 7/8 = 13/12
10) x - -6/15 = 4/27 11) -\(\dfrac{-6}{12}\)+ x = 9/48 12) x - 4/6 = 5/25 + -7/15
1: x=3/4-1/2=3/4-2/4=1/4
2: x-1/5=2/11
=>x=2/11+1/5=21/55
3: x-5/6=16/42-8/56
=>x-5/6=8/21-4/28=5/21
=>x=5/21+5/6=15/14
4: x/5=5/6-19/30
=>x/5=25/30-19/30=6/30=1/5
=>x=1
5: =>|x|=1/3+1/4=7/12
=>x=7/12 hoặc x=-7/12
6: x=-1/2+3/4
=>x=3/4-1/2=1/4
11: x-(-6/12)=9/48
=>x+1/2=3/16
=>x=3/16-1/2=-5/16
1)x= 1/4
2)x= 2/11+ 1/5
x= 21/55
3)x - 5/6 = 5/21
x = 5/21+5/6
x = 15/14
4)x/5 = 5/6 + -19/30
x:5 = 1/5
x = 1/5.5
x = 1
5) |x| - 1/4 = 6/18
|x| = 6/18 - 1/4
|x| =7/12
⇒x= 7/12 hoặc -7/12
6)x = -1/2 +3/4
x= 1/4
7) x/15 = 3/5 + -2/3
x:15 = -1/15
x = -1/15. 15
x = -1
8)11/8 + 13/6 = 85/x
85/24 = 85/x
⇒ x = 24
9) x - 7/8 = 13/12
x = 13/12 + 7/8
x = 47/24
10)x - -6/15 = 4/27
x = 4/27 + (-6/15)
x = -34/135
11) -(-6/12)+x = 9/48
x= 9/48 - 6/12
x = -5/16
12) x - 4/6 = 5/25 + -7/15
x -4/6 = -4/15
x = -4/15 + 4/6
x = 2/5
Tính:
a) 2^5 x 13^12 x 7^8 : 2^7 x 13^10 x 7^9
b) 2^n x 11 x 3 : 6^n x 3
c) 5^5 x 7 x 9^5 : 15^10
d) 7 x 8^10 x 27^9 - 8 x 9^13 x 2^27 : 7 x 6^26 x 2^2 - 2^4 x 8^3 x 27^9
e) 2^2^1^2015
f) 2015^0^2015^0^2015
a,x-10/1994+x-8/1996+x-6/1998+x-4/2000+x-2/2002=x-2002/2+x-2000/4+x-1998/6+x-1996/8+x-1994/10
b,x-1991/9+x-1993/7+x-1995/5+x-1997/3+x-1999/1=x-9/1991+x-7/1993+x-5/1995+x-3/1997+x-1/1999
c,x-1/13-2x-13/15=3x-15/27-4x-27/29