Tìm x biết :
a, ( x + 1 )2 = ( x + 1 )4
b, ( x - 2 )5 = ( x - 2 )3
c, ( 2x - 1 )2 = ( 2x - 1 )4
5: Tìm x biết a) x/3 =4/12 b) x-1/ x-2=3/5 c) 2x :6=1/4 d) x² +x/2x²+1=1/2
a) \(\dfrac{x}{3}=\dfrac{4}{12}\Rightarrow x=\dfrac{4}{12}\cdot3=\dfrac{12}{12}=1\)
b) \(\dfrac{x-1}{x-2}=\dfrac{3}{5}\) (Điều kiện : \(x\ne2\))
\(\Rightarrow5\left(x-1\right)=3\left(x-2\right)\)
\(\Leftrightarrow5x-5=3x-6\Leftrightarrow5x-3x=-6+5\Leftrightarrow2x=-1\Leftrightarrow x=-\dfrac{1}{2}\)
c) \(2x:6=\dfrac{1}{4}\Leftrightarrow2x=\dfrac{1}{4}\cdot6=\dfrac{6}{4}=\dfrac{3}{2}\Leftrightarrow x=\dfrac{3}{2}:2=\dfrac{3}{2}\cdot\dfrac{1}{2}=\dfrac{3}{4}\)
d) \(\dfrac{x^2+x}{2x^2+1}=\dfrac{1}{2}\)
\(\Rightarrow2\left(x^2+x\right)=2x^2+1\)
\(\Leftrightarrow2x^2+2x=2x^2+1\)
\(\Leftrightarrow2x^2+2x-2x^2=1\Leftrightarrow2x=1\Leftrightarrow x=\dfrac{1}{2}\).
Tìm x biết
a, 1/2( x+2 ) - 4( x-1/4 ) = 1/2x
b,5/2( x - 3/5 ) - 1/10 = x-3
c, 5/3( 3x - 3 ) + 1/2 = 1/2( 2x - 1 )
Tìm x: a)(2x+1)(1-2x)+(1-2x)^2=18
b) 2(x+1)^2-(x-3)(x+3)-(x-4)^2=0
c) (x-5)^2-x(x-4)=9
d) (x-5)^2+(x-4)(1-x)=0
a) (2x + 1)(1 - 2x) + (1 - 2x)2 = 18
= ( 1 - 2x) \(\left[\left(2x+1+1-2x\right)\right]\) = 18
= 2(1 - 2x) - 18 = 0
= 2 - 4x - 18 = 0
= -16 - 4x = 0
= -4x = 16
= x = \(\dfrac{16}{-4}=-4\)
b) 2(x + 1)2 -(x - 3)(x + 3) - (x - 4)2 = 0
= 2 (x2 + 2x + 1) - (x2 - 9) - (x2 - 8x + 16) = 0
= 2x2 + 4x + 2 - x2 + 9 - x2 + 8x - 16 = 0
= 12x - 5 = 0
= 12x = 5
= x = \(\dfrac{5}{12}\)
c) (x - 5)2 - x(x - 4) = 9
= x2 - 10x + 25 - x2 + 4x - 9 = 0
= -6x + 16 = 0
= -6x = -16
= x = \(\dfrac{-16}{-6}=\dfrac{8}{3}\)
d) (x - 5)2 + (x - 4)(1 - x)
= x2 - 10x + 25 + 5x - x2 - 4 = 0
= -5x + 21 = 0
= -5x = -21
= x = \(\dfrac{-21}{-5}=\dfrac{21}{5}\)
Chúc bạn học tốt
Tìm x biết:
a; 3x.(2x+3)-(2x+5x).(3x-2)=8
b;4.(x-1)-3.(x^2-5)_x^2=(x-3)-(x+4)
c; 2.(3x-1).(2x+5)-6.(2x-1).(x+2)=-6
d; 3.(2x-1).(3x-1)-(2x-3.(9x-1)-3=3
Tìm x biết
A. 2.(3x-1)-5(x-3)-9(2x-4)=24
B. 2x2 +4( x2 -1)=2x (3x+ 1)
C. 2x (5-3x)+2x (3x-5)-3(x-7)=4
Đ. 5x(x+1)-4x(x+2=1-x
không ai trả lời
a,\(2\left(3x-1\right)-5\left(x-3\right)-9\left(2x-4\right)=24\)
\(< =>6x-2-5x+15-18x+36=24\)
\(< =>-29x+49=24< =>29x=25< =>x=\frac{25}{29}\)
b,\(2x^2+4\left(x^2-1\right)=2x\left(3x+1\right)\)
\(< =>2x^2+4x^2-4=6x^2+2x\)
\(< =>2x=-4< =>x=-\frac{4}{2}=-2\)
c, \(2x\left(5-3x\right)+2x\left(3x-5\right)-3\left(x-7\right)=4\)
\(< =>10x-6x^2+6x^2-10x-3x+21=4\)
\(< =>-3x=4-21=-17< =>x=\frac{17}{3}\)
d, \(5x\left(x+1\right)-4x\left(x+2\right)=1-x\)
\(< =>5x^2+5x-4x^2-8x=1-x\)
\(< =>x^2-3x+x-1=0\)
\(< =>x^2-2x-1=0\)
\(< =>\left(x-1\right)^2=2\)
\(< =>\orbr{\begin{cases}x-1=\sqrt{2}\\x-1=-\sqrt{2}\end{cases}}\)
\(< =>\orbr{\begin{cases}x=1+\sqrt{2}\\x=1-\sqrt{2}\end{cases}}\)
Sai rồi bn:)
a, \(2\left(3x-1\right)-5\left(x-3\right)-9\left(2x-4\right)=24\)
\(\Leftrightarrow6x-2-5x+15-18x+36=24\)
\(\Leftrightarrow-17x+25=0\Leftrightarrow x=\frac{25}{17}\)
b, \(2x^2+4\left(x^2-1\right)=2x\left(3x+1\right)\)
\(\Leftrightarrow2x^2+4x^2-4=6x^2+2x\)
\(\Leftrightarrow-4-2x=0\Leftrightarrow x=-2\)
c, \(2x\left(5-3x\right)+2x\left(3x-5\right)-3\left(x-7\right)=4\)
\(\Leftrightarrow10x-6x^2+6x^2-10x-3x+21=4\)
\(\Leftrightarrow-3x+17=0\Leftrightarrow x=\frac{17}{3}\)
d, \(5x\left(x+1\right)-4x\left(x+2\right)=1-x\)
\(\Leftrightarrow5x^2+5x-4x^2-8x=1-x\)
\(\Leftrightarrow x^2-3x-1+x=0\Leftrightarrow x^2-2x-1=0\)
\(\Leftrightarrow x^2-2x+1-2=0\Leftrightarrow\left(x-1\right)^2=2\)
\(\Leftrightarrow\orbr{\begin{cases}x-1=\sqrt{2}\\x-1=-\sqrt{2}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\sqrt{2}+1\\x=-\sqrt{2}+1\end{cases}}}\)
B1:tìm x biết a, (-2+x^2)(x^2-2)(x^2-2)(x^2-2)(x^2-2)=1 b, (2x+3)(x-4)+(x-5)(x-2)=(3x-5)(x-4) c,(8x-3)(3x+2)-(4x+7)(x+4)=(4x+1)(5x-1) d, 2x^2+3(x-1)(x+1)=5x(x+1) e, (8-5x)(x+2)+4(x-2)(x+1)=(2+x)(2-x) f, 4(x-1)(x+5)-(x+2)(x+5)=3(x-1)(x+2)
Bạn nên viết lại đề bài cho sáng sủa, rõ ràng để người đọc dễ hiểu hơn.
f: =>4(x^2+4x-5)-x^2-7x-10=3(x^2+x-2)
=>4x^2+16x-20-x^2-7x-10-3x^2-3x+6=0
=>6x-24=0
=>x=4
e: =>8x+16-5x^2-10x+4(x^2-x-2)=4-x^2
=>-5x^2-2x+16+4x^2-4x-8=4-x^2
=>-6x+8=4
=>-6x=-4
=>x=2/3
d: =>2x^2+3x^2-3=5x^2+5x
=>5x=-3
=>x=-3/5
b: =>2x^2-8x+3x-12+x^2-7x+10=3x^2-12x-5x+20
=>-12x-2=-17x+20
=>5x=22
=>x=22/5
Chúng ta sẽ giải từng phương trình một:
a. Đặt , ta có:
Tìm x biết a) x(x-25)=0 b)2x(x-4)-x(2x-1)=-28 c)x^2 -5x=0 d)(x-2)^2-(x+1)(x+3)=-7 e)(3x+5).(4-3x)=0 f)x^2-1/4=0
a: \(x\in\left\{0;25\right\}\)
c: \(x\in\left\{0;5\right\}\)
bài 1 :tìm x , biết :
(x-7)^ x+1(x-7)^x+11=0
bài 2 :tìm x , biết :
a,|2x-3| > 5 c,|3x-1| ≤ 7 d,|3x-5| + |2x+3| = 7
bài 3 :
a,tính tổng S = 1 + 5^2 + 5^4 + ....... + 5^200.
b,so sánh 2^30 + 3^30 + 4^30 và 3.24^10
Tìm x biết
a,|x-1|+2x=3
b,|x+1|+|x+3|=10-4x
c,|x+1++3|x-2|-5|4-x|=13-2x
d,3|x-2|-2.|x+5|+4.|x-1|=9-7x
a,x=\(\frac{4}{3}\)
b, x= 1
c, x= viết đề rõ hơn
d, \(\frac{13}{6}\)
Bài 1 : Tìm thương Q và dư R sao cho A= B.Q+R biết ;
a) A = \(x^4+3x^3+2x^2-x-4\) và B = \(x^2-2x+3\)
b) A = \(2x^3-3x^2+6x-4\) và B = \(x^2-x+3\)
c) A = \(2x^4+x^3+3x^2+4x+9\) và B = \(x^2+1\)
d) A = \(2x^3-11x^2+19x-6\) và B = \(x^2-3x+1\)
c) A= \(2x^4-x^3-x^2-x+1\) và B = \(x^2+1\)