tìm x
x*2+x*3=4
x*9-1,5=30
Tìm x a) (x-1/3).(x+2/3)=0 b) (3/4x-9/16).(1,5+(-3):x)=0
\(a,\left(x-\dfrac{1}{3}\right)\left(x+\dfrac{2}{3}\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=-\dfrac{2}{3}\end{matrix}\right.\\ b,\left(\dfrac{3}{4}x-\dfrac{9}{16}\right)\left(1,5+\dfrac{-3}{x}\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}\dfrac{3}{4}x=\dfrac{9}{16}\\-\dfrac{3}{x}=-1,5=-\dfrac{3}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{4}\\x=2\end{matrix}\right.\)
a: \(\left(x-\dfrac{1}{3}\right)\left(x+\dfrac{2}{3}\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=-\dfrac{2}{3}\end{matrix}\right.\)
b: \(\left(\dfrac{3}{4}x-\dfrac{9}{16}\right)\left(\dfrac{1}{5}+\left(-3\right):x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{3}{4}x=\dfrac{9}{16}\\\left(-3\right):x=-\dfrac{1}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{16}:\dfrac{3}{4}=\dfrac{9}{16}\cdot\dfrac{4}{3}=\dfrac{3}{4}\\x=\left(-3\right):\dfrac{-1}{5}=15\end{matrix}\right.\)
tìm x , biết
a. 4x(x-5)-(x-1)(4x-3)=5
b. (3x-4)(x-2) = 3x(x-9)-3
c.2(x+3)-x2 -3x=0
d. 8x3-50x=0
e. (4x-30)2-3x(3-4x)
\(a,\Rightarrow4x^2-20x-4x^2+3x+4x-3=5\\ \Rightarrow-13x=8\Rightarrow x=-\dfrac{8}{13}\\ b,\Rightarrow3x^2-10x+8-3x^2+27x=-3\\ \Rightarrow17x=-11\Rightarrow x=-\dfrac{11}{17}\\ c,\Rightarrow\left(x+3\right)\left(2-x\right)=0\Rightarrow\left[{}\begin{matrix}x=-3\\x=2\end{matrix}\right.\\ d,\Rightarrow2x\left(4x^2-25\right)=0\\ \Rightarrow2x\left(2x-5\right)\left(2x+5\right)=0\Rightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{2}{5}\\x=-\dfrac{2}{5}\end{matrix}\right.\\ e,Sửa:\left(4x-3\right)^2-3x\left(3-4x\right)=0\\ \Rightarrow\left(4x-3\right)^2+3x\left(4x-3\right)=0\\ \Rightarrow\left(4x-3\right)\left(7x-3\right)=0\Rightarrow\left[{}\begin{matrix}x=\dfrac{3}{4}\\x=\dfrac{3}{7}\end{matrix}\right.\)
a.
4x(x-5) - (x-1)(4x-3)-5=0
4x^2-20x-4x^2+3x+4x+3=0
(4x^2-4x^2)+(-20x+3x+4x)+3=0
13x+3 = 0
13x=-3
x=-3/13
b,
(3x-4)(x-2)-3x(x-9)+3=0
3x^2-6x-4x+8 - 3x^2+27x+3=0
(3x^2-3x^2)+(-6x-4x+27x)+(8+3)=0
17x+11=0
17x=-11
x=-11/17
c, 2(x+3)-x^2-3x=0
2(x+3) - x(x+3)=0
(x+3)(2-x)=0
TH1: x+3 = 0; x=-3
TH2: 2-x=0;x=2
Tìm x:
2x^3+3x^2+2x+3=0
x^3-4x-14x(x-2)
(x-1,5)+2(15-x)^2=0
9(x-3)^2-4(x+1)^2
Tìm x
a,(7x+4)^2-(7x+4)(7x-4)=0
b, 5( x + 3 )( x - 3 ) + ( 2x + 3 )^2+(x-6)^=10
c, (x + 1)^3 + (x – 2)^3 – 2x^2 (x – 1,5) = 3
d,( x + 2)(x^2 – 2x + 4)(x – 2)(x^2 + 2x + 4) = – 65
e, 4x^2 + 4x – 5 = 2
f,16x^2 – 9(x + 1)^2 = 0
Các bạn giúp mình vs mai mình phải nộp rùii
f: Ta có: \(16x^2-9\left(x+1\right)^2=0\)
\(\Leftrightarrow\left(4x-3x-3\right)\left(4x+3x+3\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(7x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{3}{7}\end{matrix}\right.\)
Tìm x:
a) x+ 30%x= -1.3
b) x - 25%x= 1/2
c) làm 2 cách: x-1,5= 2/3x +6
d) -3/4x+12= 2x - 5
e) -6/5x+8=x-7/2
a) x + 30% = -1,3
suy ra: x + 3/10 = -13/10
x = -13/10 - 3/10
x = -8/5
b) x - 25% x = 1/2
suy ra : 1x -1/4x = 1/2
x(1-1/4) = 1/2
x = 1/2 : 3/4
x= 2/3
: Tìm x, biết:
a) 3x( 4x- 1) - 2x(6x- 3 )=30 b) 2x(3-2x) + 2x(2x-1)=15
c) (5x-2)(4x-1) + (10x +3)(2x - 1)=1 d) (x+2) (x+2)- (x -3)(x+1) = 9
e) (4x+1)(6x-3) = 7 + (3x – 2)(8x + 9) g) (10x+2)(4x- 1)- (8x -3)(5x+2) =14
`@` `\text {Ans}`
`\downarrow`
`a)`
`3x(4x-1) - 2x(6x-3) = 30`
`=> 12x^2 - 3x - 12x^2 + 6x = 30`
`=> 3x = 30`
`=> x = 30 \div 3`
`=> x=10`
Vậy, `x=10`
`b)`
`2x(3-2x) + 2x(2x-1) = 15`
`=> 6x- 4x^2 + 4x^2 - 2x = 15`
`=> 4x = 15`
`=> x = 15/4`
Vậy, `x=15/4`
`c)`
`(5x-2)(4x-1) + (10x+3)(2x-1) = 1`
`=> 5x(4x-1) - 2(4x-1) + 10x(2x-1) + 3(2x-1)=1`
`=> 20x^2-5x - 8x + 2 + 20x^2 - 10x +6x - 3 =1`
`=> 40x^2 -17x - 1 = 1`
`d)`
`(x+2)(x+2)-(x-3)(x+1)=9`
`=> x^2 + 2x + 2x + 4 - x^2 - x + 3x + 3=9`
`=> 6x + 7 =9`
`=> 6x = 2`
`=> x=2/6 =1/3`
Vậy, `x=1/3`
`e)`
`(4x+1)(6x-3) = 7 + (3x-2)(8x+9)`
`=> 24x^2 - 12x + 6x - 3 = 7 + (3x-2)(8x+9)`
`=> 24x^2 - 12x + 6x - 3 = 7 + 24x^2 +11x - 18`
`=> 24x^2 - 6x - 3 = 24x^2 + 18x -11`
`=> 24x^2 - 6x - 3 - 24x^2 + 18x + 11 = 0`
`=> 12x +8 = 0`
`=> 12x = -8`
`=> x= -8/12 = -2/3`
Vậy, `x=-2/3`
`g)`
`(10x+2)(4x- 1)- (8x -3)(5x+2) =14`
`=> 40x^2 - 10x + 8x - 2 - 40x^2 - 16x + 15x + 6 = 14`
`=> -3x + 4 =14`
`=> -3x = 10`
`=> x= - 10/3`
Vậy, `x=-10/3`
Tìm x biết:
1)3/4x-1/4=2(x-3)+1/4x
2)30%.x-x+5/6=1/3
3)(2.x-1).(3.x+9)=0
Bài 1: Tìm x : A) 25%x+4x=35-0,75x
B) 3/4.(x-2) - 1/2.(6-2x)=1/6x + 5
C) -1/2.(3x+5) - 2/3.(9-6x)= 3/5.(x-10) - 3
D) (1/4x - 1,5) + (5/6x-3) - (5/8x-0,5)= -4,5
Tìm x biết
a/3x*(12*x-4)-9*x*(4x-3)=30
b/x*(5-2*x)+2*x*(x-1)=15
a/3x(12x - 4 ) -9x (4x -3 ) = 30
<=> 36x^2 - 12x - 36x²+27x = 30
<=> 15x = 30
<=> x=2
b/ => 5x -2. x^2 + 2.x^2 -2x = 15
=> 5x -2x = 15
=> 3x = 15 => x= 5
a/3x(12x - 4 ) -9x (4x -3 ) = 30
36x^2 - 12x - 36x²+27x = 30
15x = 30
x=2
b/ 5x -2. x^2 + 2.x^2 -2x = 15
5x -2x = 15
3x = 15 => x= 5