tìm x
4.(5-x)-3.(1-x)= -3^2
Tìm x, biết:
a.1/4+3/4.x=3/2-x
b.3/5.x-1/4=1/10.x-1/2
c.3x-3/5=x-1/4
d.3/2.x-2/5=1/3.x-1/4
`@` ` \text {Ans}`
`\downarrow`
`a,`
`1/4+3/4*x=3/2-x`
`=> 1/4 + 3/4x - 3/2 + x = 0`
`=> (1/4 - 3/2) + (3/4x + x) = 0`
`=> -5/4 + 7/4x = 0`
`=> 7/4x = 5/4`
`=> x = 5/4 \div 7/4`
`=> x = 5/7`
Vậy, `x=5/7`
`b,`
`3/5*x-1/4=1/10*x-1/2`
`=> 3/5x - 1/4 - 1/10x + 1/2 = 0`
`=> (3/5x - 1/10x) + (-1/4 + 1/2)=0`
`=> 1/2x + 1/4 = 0`
`=> 1/2x = -1/4`
`=> x = -1/4 \div 1/2`
`=> x = -1/2`
Vậy, `x=-1/2`
`c,`
`3x-3/5=x-1/4`
`=> 3x - 3/5 - x + 1/4 = 0`
`=> (3x - x) - (3/5 - 1/4) = 0`
`=> 2x - 7/20 = 0`
`=> 2x = 0,35`
`=> x = 0,35 \div 2`
`=> x = 7/40`
Vậy, `x=7/40`
`d,`
`3/2*x-2/5=1/3*x-1/4`
`=> 3/2x - 2/5 - 1/3x + 1/4 = 0`
`=> (3/2x - 1/3x) - (2/5 - 1/4) = 0`
`=> 7/6x - 3/20 = 0`
`=> 7/6x = 3/20`
`=> x = 3/20 \div 7/6`
`=> x = 9/70`
Vậy, `x=9/70`
`@` `\text {Kaizuu lv uuu}`
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
tìm x , biết
a) 17/6- x( x-7/6)= 7/4
b) 3/35 - ( 3/5-x)= 2/7
tìm x thuộc Z , biết
3/4-5/6 < x/12 < 1 -( 2/3-1/4)
tìm x biết
a ) 2x-3=x + 1/2
b) 4x- ( x+ 1/2) = 2x - ( 1/2 - 5 )
Bài 1:
a) Ta có: \(\dfrac{17}{6}-x\left(x-\dfrac{7}{6}\right)=\dfrac{7}{4}\)
\(\Leftrightarrow\dfrac{17}{6}-x^2+\dfrac{7}{6}x-\dfrac{7}{4}=0\)
\(\Leftrightarrow-x^2+\dfrac{7}{6}x+\dfrac{13}{12}=0\)
\(\Leftrightarrow-12x^2+14x+13=0\)
\(\Delta=14^2-4\cdot\left(-12\right)\cdot13=196+624=820\)
Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:
\(\left\{{}\begin{matrix}x_1=\dfrac{14-2\sqrt{205}}{-24}=\dfrac{-7+\sqrt{205}}{12}\\x_2=\dfrac{14+2\sqrt{2015}}{-24}=\dfrac{-7-\sqrt{205}}{12}\end{matrix}\right.\)
b) Ta có: \(\dfrac{3}{35}-\left(\dfrac{3}{5}-x\right)=\dfrac{2}{7}\)
\(\Leftrightarrow\dfrac{3}{5}-x=\dfrac{3}{35}-\dfrac{10}{35}=\dfrac{-7}{35}=\dfrac{-1}{5}\)
hay \(x=\dfrac{3}{5}-\dfrac{-1}{5}=\dfrac{3}{5}+\dfrac{1}{5}=\dfrac{4}{5}\)
Bài 3:
a) Ta có: \(2x-3=x+\dfrac{1}{2}\)
\(\Leftrightarrow2x-x=\dfrac{1}{2}+3\)
\(\Leftrightarrow x=\dfrac{7}{2}\)
b) Ta có: \(4x-\left(x+\dfrac{1}{2}\right)=2x-\left(\dfrac{1}{2}-5\right)\)
\(\Leftrightarrow3x-\dfrac{1}{2}-2x+\dfrac{1}{2}-5=0\)
\(\Leftrightarrow x=5\)
tìm x: {x^2 - [5^2 - (4^2 -3 x 5 )^2 - 3 x 2^3]^4 - 2^4 x 3 }^3 = 1
a) \(\dfrac{1}{2}+x=\dfrac{5}{6}\)
\(\Rightarrow x=\dfrac{5}{6}-\dfrac{1}{2}=\dfrac{5}{6}-\dfrac{3}{6}=\dfrac{2}{6}=\dfrac{1}{3}\)
b) \(x+\dfrac{1}{4}=\dfrac{3}{4}\)
\(\Rightarrow x=\dfrac{3}{4}-\dfrac{1}{4}=\dfrac{2}{4}=\dfrac{1}{2}\)
c) \(x-\dfrac{1}{5}=\dfrac{3}{10}\)
\(\Rightarrow x=\dfrac{3}{10}+\dfrac{1}{5}=\dfrac{3}{10}+\dfrac{2}{10}=\dfrac{5}{10}=\dfrac{1}{2}\)
d) \(\dfrac{5}{6}-x=\dfrac{1}{3}\)
\(\Rightarrow x=\dfrac{5}{6}-\dfrac{1}{3}=\dfrac{5}{6}-\dfrac{2}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)
e) \(\dfrac{3}{10}+x=\dfrac{1}{2}\)
\(\Rightarrow x=\dfrac{1}{2}-\dfrac{3}{10}=\dfrac{5}{10}-\dfrac{3}{10}=\dfrac{2}{10}=\dfrac{1}{5}\)
g) \(x+\dfrac{1}{4}=\dfrac{3}{8}\)
\(\Rightarrow x=\dfrac{3}{8}-\dfrac{1}{4}=\dfrac{3}{8}-\dfrac{2}{8}=\dfrac{1}{8}\)
a) ⇒x=56−12=56−36=26=13⇒x=56−12=56−36=26=13
b) ⇒x=34−14=24=12⇒x=34−14=24=12
c) ⇒x=310+15=310+210=510=12⇒x=310+15=310+210=510=12
d) ⇒x=56−13=56−26=36=12⇒x=56−13=56−26=36=12
e) ⇒x=12−310=510−310=210=15⇒x=12−310=510−310=210=15
g) ⇒x=38−14=38−28=18⇒x=38−14=38−28=18
Đọc tiếp
a) ⇒x=56−12=56−36=26=13⇒x=56−12=56−36=26=13
b) ⇒x=34−14=24=12⇒x=34−14=24=12
c) ⇒x=310+15=310+210=510=12⇒x=310+15=310+210=510=12
d) ⇒x=56−13=56−26=36=12⇒x=56−13=56−26=36=12
e) ⇒x=12−310=510−310=210=15⇒x=12−310=510−310=210=15
g) ⇒x=38−14=38−28=18⇒x=38−14=38−28=18
Tìm x :
a, x - 3/2 = 4/3 b, 2/5 * x = 1/3
c, x - 4/9 = 3/7 : 9/14 d, 3/5 * x - 1/2 = 1/5
a) x - 3/2 = 4/3
x = 4/3 + 3/2
x = 8/6 + 9/6 = 17/6
b) 2/5 * x = 1/3
x = 1/3 : 2/5
x = 1/3 x 5/2 = 5/6
c) x - 4/9 = 3/7 : 9/14
x - 4/9 = 2/3
x = 2/3 + 4/9
x = 6/9 + 4/9 = 10/9
d) 3/5 * x - 1/2 = 1/5
3/5 * x = 1/5 + 1/2 = 7/10
x = 7/10 : 3/5
x = 7/10 * 5/3 = 7/6
a/\(x-\dfrac{3}{2}=\dfrac{4}{3}\)
\(x=\dfrac{4}{3}+\dfrac{3}{2}\)
\(x=\dfrac{17}{6}\)
b/\(\dfrac{2}{5}\times x=\dfrac{1}{3}\)
\(x=\dfrac{1}{3}:\dfrac{2}{5}\)
\(x=\dfrac{5}{6}\)
c/\(x-\dfrac{4}{9}=\dfrac{3}{7}:\dfrac{9}{14}\)
\(x-\dfrac{4}{9}=\dfrac{2}{3}\)
\(x=\dfrac{2}{3}+\dfrac{4}{9}\)
\(x=\dfrac{10}{9}\)
d/\(\dfrac{3}{5}\times x-\dfrac{1}{2}=\dfrac{1}{5}\)
\(\dfrac{3}{5}\times x=\dfrac{1}{5}+\dfrac{1}{2}\)
\(\dfrac{3}{5}\times x=\dfrac{7}{10}\)
\(x=\dfrac{7}{10}:\dfrac{3}{5}\)
\(x=\dfrac{7}{6}\)
a,x=\(\dfrac{17}{6}\)b,x=\(\dfrac{5}{6}\)c,x=\(\dfrac{10}{9}\)d,x=\(\dfrac{7}{6}\)
Tìm x, biết :
a) (x-2)3 +6(x+1)2-x3+12=0
b) (x-5) (x+5) - (x+3)2+3(x-2)2=(x+1)2- (x+4)(x-4)+3x2
c) (2x+3)2 +(x-1)(x+1)=5(x+2)2-(x-5)(x+1)+(x+4)
d) (1-3x)2-(x-2)(9x+1)=(3x-4)(3x+4)-9(x+3)2
Giúp mk với ạ, mk cảm ơn !
a) (x-2)3+6(x+1)2-x3+12=0
\(\Rightarrow\)x3-6x2+12x-8+6(x2+2x+1)-x3+12=0
\(\Rightarrow\)x3-6x2+12x-8+6x2+12x+6-x3+12=0
\(\Rightarrow\)24x+10=0
\(\Rightarrow\)24x=-10
\(\Rightarrow\)x=\(\dfrac{-10}{24}=\dfrac{-5}{12}\)
b)(x-5)(x+5)-(x+3)2+3(x-2)2=(x+1)2-(x-4)(x+4)+3x2
\(\Rightarrow\)x2-25-(x2+6x+9)+3(x2-4x+4)=x2+2x+1-(x2-16)+3x2
\(\Rightarrow\)x2-25-x2-6x-9+3x2-12x+12=x2+2x+1-x2+16+3x2
\(\Rightarrow\)3x2-18x-22=3x2+2x+17
\(\Rightarrow\)3x2-18x-22-3x2-2x-17=0
\(\Rightarrow\)-20x-39=0
\(\Rightarrow\)-20x=39
\(\Rightarrow\)x=\(-\dfrac{39}{20}\)
c) (2x+3)2 +(x-1)(x+1)=5(x+2)2-(x-5)(x+1)+(x+4)
⇒4x2+12x+9+x2-1=5(x2+4x+4)-(x2+x-5x-5)+x+4
⇒5x2+12x+8=5x2+20x+20-x2-x+5x+5+x+4
⇒5x2+12x+8-5x2-20x-20+x2+x-5x-5-x-4=0
⇒x2-13x-21=0
Bài 1: Tìm x, biết 4 – 2(x + 1) = 2
Bài 2. Tìm x biết: |2x – 3| - 1 = 2
Bài 3. Tìm x, biết: 3 1 3 x + 16 3 4 = - 13,25
Bài 4: Tìm x biết: 60% x + 2 3 x = - 76
Bài 5: Tìm x, biết: a) 11 - (-53 + x) = 97 b) -(x + 84) + 213 = -16
thanks
Bài 1:
Ta có: \(4-2\left(x+1\right)=2\)
\(\Leftrightarrow2\left(x+1\right)=2\)
\(\Leftrightarrow x+1=1\)
hay x=0
Bài 2:
Ta có: \(\left|2x-3\right|-1=2\)
\(\Leftrightarrow\left|2x-3\right|=3\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-3=3\\2x-3=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=6\\2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=0\end{matrix}\right.\)
tìm x
a) -1/8 = 3/x b) x/3 = 3/x c)3/4 . x = 1 và 1/2
d) x - 3/10 = 7/15 : 3/5 e) -4/7 - x = -8/3 . 3/7
f) 4/7 . x - 2/3 = 1/5 g) 2/3 + 1/3 : 3 x = 1/5
h) 2/9 - 7/8 x=1/3 j) (2 và 4/5 x - 50) : 2/3 = 51
\(a,\dfrac{-1}{8}=\dfrac{3}{x}\\ \dfrac{3}{-24}=\dfrac{3}{x}\\ x=-24\\ b,\dfrac{x}{3}=\dfrac{3}{x}\\ x.x=3.3\\ x^2=9\\ x=\pm3\\ c,\dfrac{3}{4}.x=1\dfrac{1}{2}\\ \dfrac{3}{4}.x=\dfrac{3}{2}\\ x=\dfrac{3}{2}:\dfrac{3}{4}\\ x=2\\ d,x-\dfrac{3}{10}=\dfrac{7}{15}:\dfrac{3}{5}\\ x-\dfrac{3}{10}=\dfrac{7}{9}\\ x=\dfrac{7}{9}+\dfrac{3}{10}\\ x=\dfrac{97}{90}\\ e,\dfrac{-4}{7}-x=\dfrac{-8}{3}.\dfrac{3}{7}\\ \dfrac{-4}{7}-x=\dfrac{-8}{7}\\ x=\dfrac{-4}{7}+\dfrac{8}{7}\\ x=\dfrac{4}{7}\\ \)
f: =>x*4/7=1/5+2/3=3/15+10/15=13/15
=>x=91/60
g: =>1/3:3x=1/5-2/3=-7/15
=>3x=-5/7
=>x=-5/21
h: =>7/8x=-1/9
=>x=-1/9:7/8=-1/9*8/7=-8/63
j: =>(2,8x-50)=34
=>2,8x=84
=>x=30
Tìm x biết :
x + 4/5 = 4/5 + ( 3/7 + 3/5 ) 5/7 + x/35 = 4/5
x < 3/4 + 2 2/3 + 1 < x < 5/6 + 4
x< 5/6 - 3/4 2/3 < x < 2 - 5/6
a: =>x=3/7+3/5=15/35+21/35=36/35
b: =>x/35=4/5-5/7=28/35-25/35=3/35
=>x=3
c: =>x<3/4+8/4=11/4
=>\(x\in\left\{0;1;2;3\right\}\)
d: =>5/3<x<5/6+24/6=29/6
=>\(x\in\left\{2;3;4\right\}\)
e: =>x<10/12-9/12=1/12
=>x=0
f: =>2/3<x<12/6-5/6=7/6
=>x=1