a,3/2(x+7)=x+7/6
b,9/4. /x/-4=1/4./x/
c,3/(-2)^2-(1/4-x)^2=1-1/2
a) -5/8 + x = -7/6
b) x - -3/4 = -14/25
c) x. 9/-13 = -33/26
d) 4/-9 : x = -5/3
e) 4/7 .x - 2/3 = 1/5
f) 4/5 + 5/7 : x = 1/6
a: =>x=-7/6+5/8=-13/24
b: =>x=-14/25-3/4=-131/100
c: \(x=\dfrac{-33}{26}:\dfrac{-9}{13}=\dfrac{33}{26}\cdot\dfrac{13}{9}=\dfrac{11}{3}\cdot\dfrac{1}{2}=\dfrac{11}{6}\)
d: \(x=\dfrac{4}{9}:\dfrac{5}{3}=\dfrac{4}{9}\cdot\dfrac{3}{5}=\dfrac{12}{45}=\dfrac{4}{15}\)
Bài 1
A) 3/2+9/2 -6
B) -5/4:(1/4-7/8)+3/2 x(1/3-5/6)
C) (-2,5)x0,65 -1.5 x 0,3+(-0,35)x1,5
a: =6-6=0
b: \(=\dfrac{-5}{4}:\dfrac{2-7}{8}+\dfrac{3}{2}\cdot\dfrac{2-5}{6}\)
\(=\dfrac{-5}{4}\cdot\dfrac{8}{-5}+\dfrac{3}{2}\cdot\dfrac{-3}{6}\)
\(=2+\dfrac{-9}{12}=2-\dfrac{3}{4}=\dfrac{5}{4}\)
c: \(=2,5\cdot\left(-0,65\right)+1,5\left(-0,3-0,35\right)=-0,65\cdot4=-2,6\)
a)2x-3/4-4x-5/3=5-x/6
b)3(x-1^2)=16
c)(x+7)(x-4)=2(x-4)
d)4x^2-3x-1=0
`a)[2x-3]/4-[4x-5]/3=[5-x]/6`
`<=>3(2x-3)-4(4x-5)=2(5-x)`
`<=>6x-9-16x+20=10-2x`
`<=>8x=1`
`<=>x=1/8`
(`b->c` mk đã làm r).
Tính :
a) 13/15 + 4/7 - 101/105 b) 2/5 + 3/5 + x 4/9 c) 3/4 x 5/2 x 7/6
d) 1/2 : 1/4 - 2/9 e) 2/3 - 1/4 +2/9 g) 5/2 + 1/3 x 3/2
a: =91/105+60/105-101/105
=50/105=10/21
c: \(\dfrac{3}{4}\cdot\dfrac{5}{2}\cdot\dfrac{7}{6}=\dfrac{3}{6}\cdot\dfrac{7}{2}\cdot\dfrac{5}{4}=\dfrac{1}{2}\cdot\dfrac{7}{2}\cdot\dfrac{5}{4}=\dfrac{35}{16}\)
d: =2-2/9
=18/9-2/9
=16/9
e: =24/36-9/36+8/36
=23/36
g: =5/2+1/2
=3
a: =>x+7/4=6:2/3=9
=>x=29/4
b: =>x:5/3=7/5
=>x=7/5*5/3=7/3
c:=>x+1/6=5/3
=>x=10/6-1/6=3/2
d: =>x+4/5=4/5+3/7+3/5
=>x=3/7+3/5=36/35
e: =>x/35=4/5-5/7=3/35
=>x=3
f: =>13/28+x=1/2
=>x=1/28
g: =>1/3-x=1/9
=>x=2/9
tìm x
a) X x 3/4 = 1/5 b) 3/7 x X = 2/5 c) 1/3 + 2/9 = 2/12 x X
d) 4/15 x X - 2/3 = 1/5 e) x : 1/7 = 2/3 f) 1/9 : x = 7/3 j) 1/4 + 5/12 = 8/3 : x
h) 7/4 : X - 1/2 = 1/5
a: x*3/4=1/5
=>x=1/5:3/4=1/5*4/3=4/15
b: x*3/7=2/5
=>x=2/5:3/7=2/5*7/3=14/15
c: 1/3+2/9=2/12x
=>1/6x=3/9+2/9=5/9
=>x=5/9*6=30/9=10/3
d: 4/15*x-2/3=1/5
=>4/15*x=2/3+1/5=10/15+3/15=13/15
=>4x=13
=>x=13/4
e: x:1/7=2/3
=>x=2/3*1/7=2/21
f: 1/9:x=7/3
=>x=1/9:7/3=1/9*3/7=3/63=1/21
j: 1/4+5/12=8/3:x
=>8/3:x=3/12+5/12=8/12=2/3
=>x=4
h: =>7/4:x=1/5+1/2=7/10
=>x=7/4:7/10=10/4=5/2
Bài 1. Tìm x, biết:
a/ 1/4.(x-3)+2=1/5
b/ 1/7-2.(x+1)=1/4+2/3
c/ 1/4.(2x+3)-1/9=2/5
d/ 3/2.(x+1)-4/9=2/3
e/ 4/5.(2-3x)+4/7=2và1/3
[Cần gấp ạ!]
a) 1/4(x-3)+2=1/5
1/4.(x-3) = 1/5-2
1/4.(x-3) = -9/5
x-3 = (-9/5):1/4
x-3 = -36/5
x = -36/5+3
x= -21/5
Tính:
a) 9/5 + 2/5 x 4/6
b) 3/8 x 2 - 6/7 x 1/3
a,`9/5+2/5xx4/6=9/5+4/15=27/15+4/15=31/15`
b,`3/8xx2-6/7xx1/3=3/4-2/7=21/18-8/28=13/28`
a) 9/5+ 4/15
= 27/15+4/15
= 31/15
b) 3/4- 2/7
= 13/28
\(a,=\dfrac{9}{5}+\dfrac{4}{15}=\dfrac{27}{15}+\dfrac{4}{15}=\dfrac{31}{15}\\ b,=\dfrac{3}{4}-\dfrac{2}{7}=\dfrac{13}{28}\)
1.giải các phương trình sau:
a, 3(2x+1)/4 - 5x+3/6 = 2x-1/3 - 3-x/4
b, 19/4 - 2(3x-5)/5 = 3-2x/10 - 3x-1/4
c, x-2*3/2+3 + x-3*5/3+5 + x-5*2/5+2 = 10
d, x-3/5*7 + x-5/3*7 + x-7/3*5 = 2(1/3 + 1/5 + 1/7)
2. giải các phương trình:
a, x-1/9 + x-2/8 = x-3/7 + x-4/6
b, (1/1*2 + 1/2*3 + 1/3*4 + ... + 1/9*10) (x-1) + 1/10x = x- 9/10
Câu 1 :
a, \(\frac{3\left(2x+1\right)}{4}-\frac{5x+3}{6}=\frac{2x-1}{3}-\frac{3-x}{4}\)
\(\Leftrightarrow\frac{6x+3}{4}+\frac{3-x}{4}=\frac{2x-1}{3}+\frac{5x+3}{6}\)
\(\Leftrightarrow\frac{5x+6}{4}=\frac{9x+1}{6}\Leftrightarrow\frac{30x+36}{24}=\frac{36x+4}{24}\)
Khử mẫu : \(30x+36=36x+4\Leftrightarrow-6x=-32\Leftrightarrow x=\frac{32}{6}=\frac{16}{3}\)
tương tự
\(\frac{19}{4}-\frac{2\left(3x-5\right)}{5}=\frac{3-2x}{10}-\frac{3x-1}{4}\)
\(< =>\frac{19.5}{20}-\frac{8\left(3x-5\right)}{20}=\frac{2\left(3-2x\right)}{20}-\frac{5\left(3x-1\right)}{20}\)
\(< =>95-24x+40=6-4x-15x+5\)
\(< =>-24x+135=-19x+11\)
\(< =>5x=135-11=124\)
\(< =>x=\frac{124}{5}\)
\(\frac{\left(x-2\right).3}{2}+3+\frac{\left(x-3\right).5}{3}+5+\frac{\left(x-5\right).2}{5}+2=10\)
\(< =>\frac{\left(x-2\right).3.15}{30}+\frac{\left(x-3\right).5.10}{30}+\frac{\left(x-5\right).2.6}{30}=10-2-3-5\)
\(< =>\frac{\left(x-2\right).45+\left(x-3\right).50+\left(x-5\right).12}{30}=0\)
\(< =>45x-90+50x-150+12x-60=0\)
\(< =>107x-300=0< =>x=\frac{300}{107}\)