(3-x)(x2+25)(2x+3)=0
a) x2(x - 5) + 5 - x = 0; b) 3x4 - 9x3 = -9x2 + 27x;
c) x2(x + 8) + x2 = -8x; d) (x + 3)(x2 -3x + 5) = x2 + 3x.
e) 3x(x - 1) + x - 1 = 0;
f) (x - 2)(x2 + 2x + 7) + 2(x2 - 4) - 5(x - 2) = 0;
g) (2x - 1)2 - 25 = 0;
h) x3 + 27 + (x + 3)(x - 9) = 0.
i)8x3 - 50x = 0; k) 2(x + 3)-x2 - 3x = 0;
m)6x2 - 15x - (2x - 5)(2x + 5) =
a: \(\Leftrightarrow\left(x-5\right)\left(x+1\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-1\\x=1\end{matrix}\right.\)
d: \(\Leftrightarrow\left(x+3\right)\left(x^2-4x+5\right)=0\)
\(\Leftrightarrow x+3=0\)
hay x=-3
Tìm x biết:
a) (x - 3)2 - 5.(x - 2) + 5 = 0.
b) (2x - 1)2 - 3.(x - 2).(x + 2) - 25 = 0.
c) (x - 1)3 - x2.(x - 2) + 5 = 0.
d) x2 - 4x + 5 = 0.
a) (x - 3)2 - 5.(x - 2) + 5 = 0.
<=> x^2 - 6x + 9 - 5x + 10 + 5 = 0
<=> x^2 - 11x + 24 = 0
<=> (x-3)(x-8)=0
<=> x = 3 hoặc x = 8
b) (2x - 1)2 - 3.(x - 2).(x + 2) - 25 = 0.
<=> 4x^2 - 4x + 1 - 3x^2 + 12 - 25 = 0
<=> x2 - 4x - 12 = 0
<=> (x+2)(x-6) = 0
<=> x = -2 hoặc x = 6
d) x2 - 4x + 5 = 0.
<=> (x - 2)2 = -1 (vô lý)
Vậy phương trình vô nghiệm
Tìm x, biết:
a) 3x(x - 1) + x - 1 = 0;
b) (x - 2)( x 2 + 2x + 7) + 2( x 2 - 4) - 5(x - 2) = 0;
c) ( 2 x - 1 ) 2 - 25 = 0;
d) x 3 + 27 + (x + 3)(x - 9) = 0.
a) x = 1; x = - 1 3 b) x = 2.
c) x = 3; x = -2. d) x = -3; x = 0; x = 2.
Tìm x biết :
a, (x-2).(x2 +2x +7) +2.( x2-4) -5 .(x-2) =0
b, 4x2 -25 -(2x-5) .(2x+7) =0
c, x3 +27 + (x+3) .(x-9)=0
Giải các phương trình sau:
a) x 2 –l0x = -25; b) 4 x 2 - 4x = -1;
c) ( 1 - 2 x ) 2 = ( 3 x - 2 ) 2 ; d) ( x - 2 ) 3 + ( 5 - 2 x ) 3 =0.
a) x = 5. b) x = 1 2 .
c) x = 3 5 hoặc x = 1. d) x = 3.
\(a,x^2-10x=-25\)
\(< =>x^2-10x+25=0\)
\(< =>\left(x-5\right)^2=0< =>x=5\)
b, \(4x^2-4x=-1\)
\(< =>4x^2-4x+1=0\)
\(< =>\left(2x-1\right)^2=0< =>x=\frac{1}{2}\)
c,\(\left(1-2x\right)^2=\left(3x-2\right)^2\)
\(< =>\left(1-2x\right)^2-\left(3x-2\right)^2=0\)
\(< =>\left(1-2x-3x+2\right)\left(1-2x+3x-2\right)=0\)
\(< =>\left(-5x+3\right)\left(x-1\right)=0\)
\(< =>\orbr{\begin{cases}x=\frac{3}{5}\\x=1\end{cases}}\)
d, \(\left(x-2\right)^3+\left(5-2x\right)^3=0\)
\(< =>\left(x-2+5-2x\right)\left(x^2-4x+4+5x-2x^2-10+4x+25-20x+4x^2\right)=0\)
\(< =>\left(3-x\right)\left(-5x^2-15x+19\right)=0\)
\(< =>\left(x-3\right)\left(5x^2+15x-19=0\right)\)
\(< =>\orbr{\begin{cases}x=3\\x^2+3x-\frac{19}{5}=0\end{cases}}\)
Xét phương trình \(x^2+3x-\frac{19}{5}=0< =>\left(x^2+2.x.\frac{3}{2}+\frac{9}{4}\right)-\left(\frac{19}{5}+\frac{9}{4}\right)=0\)
\(< =>\left(x+\frac{3}{2}\right)^2=\frac{29}{5}+\frac{1}{4}\)
\(< =>\orbr{\begin{cases}x=\sqrt{\frac{29}{5}+\frac{1}{4}}-\frac{3}{2}\\x=-\sqrt{\frac{29}{5}+\frac{1}{4}}-\frac{3}{2}\end{cases}}\)
Vậy .........
Tìm x biết
x2-4=0
3x2-75=0
(x+2)2=25
x2-2x-80=0
x2-12x+11=0
4x2-4x-3=0
4, x^2-10x+8x-80=0
x(x-8)+10(x-8)=0
x+10=0 =)x=-10
hoặc
x-8=0 =)x=8
1, =(x+2)(x-2)=0
x+2=0 =)x=-2
hoặc
x-2=0 =)x=2
2,3(x^2-5^2)=0
=x+5=0 =)x=-5
hoặc
x-5=0 =)x=5
3,(3+2)^2=25
5^2=25
5, x^2-x-11x+11=0
x(x-1)-11(x-1)=0
x-11=0 =)x=11
hoặc
x-1=0 =)x=1
xl nheee mk làm nhầm câu 4 trc
bn có thể viết đề rõ hơn k nhìn có vẻ rối
bài 3: Tìm x, biết:
a)(2x-1)2-25=0 b)8x3-50x=0
c)2(x+3)-x2-3x=0 d)x3+27+(x+3)(x-9)=0
mình cần gấppppppppp
bài 3: Tìm x, biết:
a)(2x-1)2-25=0 b)8x3-50x=0
c)2(x+3)-x2-3x=0 d)x3+27+(x+3)(x-9)=0
mình cần gấpppppppppp
a: Ta có: \(\left(2x-1\right)^2-25=0\)
\(\Leftrightarrow\left(2x-6\right)\left(2x+4\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-2\end{matrix}\right.\)
Tìm x biết:
a) 7x.(2x - 3) - (4x2 - 9) = 0
b) (2x - 7).(x - 2).(x2 - 4) = 0
c) (9x2 - 25) - (6x - 10) = 0
a) \(7x\left(2x-3\right)-\left(4x^2-9\right)=0\Rightarrow7x\left(2x-3\right)-\left(2x-3\right)\left(2x+3\right)=0\Rightarrow\left(2x-3\right)\left(7x-2x+3\right)=0\Rightarrow\left[{}\begin{matrix}2x-3=0\\5x+3=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{3}{5}\end{matrix}\right.\)
b) \(\left(2x-7\right).\left(x-2\right)\left(x^2-4\right)=0\Rightarrow\left(2x-7\right)\left(x-2\right)^2\left(x+2\right)=0\Rightarrow\left[{}\begin{matrix}2x-7=0\\\left(x-2\right)^2=0\\x+2=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=2\\x=-2\end{matrix}\right.\)
c)\(\left(9x^2-25\right)-\left(6x-10\right)=0\Rightarrow\left(3x-5\right)\left(3x+5\right)-2\left(3x-5\right)=0\Rightarrow\left(3x-5\right)\left(3x+5-2\right)=0\Rightarrow\left[{}\begin{matrix}3x-5=0\\3x+3=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{5}{3}\\x=1\end{matrix}\right.\)
a: Ta có: \(7x\left(2x-3\right)-\left(4x^2-9\right)=0\)
\(\Leftrightarrow7x\left(2x-3\right)-\left(2x-3\right)\left(2x+3\right)=0\)
\(\Leftrightarrow\left(2x-3\right)\left(5x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{3}{5}\end{matrix}\right.\)
b: Ta có: \(\left(2x-7\right)\left(x-2\right)\left(x^2-4\right)=0\)
\(\Leftrightarrow\left(2x-7\right)\left(x-2\right)^2\cdot\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=2\\x=-2\end{matrix}\right.\)
c: Ta có: \(\left(9x^2-25\right)-\left(6x-10\right)=0\)
\(\Leftrightarrow\left(3x-5\right)\left(3x+5-2\right)=0\)
\(\Leftrightarrow\left(3x-5\right)\left(3x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{3}\\x=-1\end{matrix}\right.\)