x^2 - 4x = 0
x^2 - 4x + 4 - 4 = 0
( x - 2 )^2 - 4 = 0
( x - 2 )^2 = 4
x - 2 = [+4; -4]
Xét x - 2 = 4
x = 6
Xét x - 2 = -4
x = -2
Vậy x thuộc 6 ; -2
x^2-4x=0
x(x-4)=0
suy ra x=0 hoặc x-4=0
x=0 hoặc x=4
giải phương trình:
a) 2/x+1 - 1/x-3= 3x-11/x^2-2x-3
b) 3/x-2 +1/x=-2/x.(x-2)
c) x-3/x+3 - 2/x-3=3x+1/9-x^2
d) 2/x+1 - 1/x-2=3x-5/x^2-x-2
e) x-2/x+2 + 3/x-2=x^2-11/x^2-4
f) x+3/x+1 + x-2/x=2
g) x+5/x-5 - x-5/x+5=20/x^2-25
h) x+4/x+1 + x/x-1=2x^2/x^2-1
i) x+1/x-1 - 1/x+1=x^2+2/x^2-1
giải các phương trình sau
1/ ( x-2)(x-5)=(x-3)(x-4)
2/ (x-7)(x+7) +x^2 -2=2(x^2+5)
3/ (x-1)^2 +(x+3)^2 =2(x-2)(x=2)
4/ (x+1)^2= (x+3)(x-2)
5/ x^2-(2x-1)(x+3)= 3-x(5+x)
6/ 3(5-2x) -4( x+2) =5x-18
Phân tích đa thức thành nhân tử:
1.45+x^3-5*x^2-9*x
2.x^4-2*x^3-2*x^2-2*x+3
3.x^4-5*x^2+4
4.x^4+64
5.x^5+x^4+1
6.(x^2+2*x)*(x^2+2*x+4)+3
7.(x^3+4*x+8)^2+3*x*(x^2+4*x+8)+2*x^2
8. x^3*(x^2-7)^2-36*x
9.x^5+x+1
10. x^8+x^4+1
11. x^5-x^4-x^3-x^2-x-2
12. x^9-x^7-x^6-x^5+x^4+x^3+x^2-1
13. (x^2-x)^2-12*(x^2-x)+24
1.Tìm x
a) (x - 5)(x + 5) - (x + 3)^2 + 3 (x - 2)^2 = (x + 1)^2 - (x + 4)(x - 4) +3x^2
b) (2x + 3)^2 + (x - 1)(x + 1) = 5 (x + 2)^2 - (x - 5)(x + 1) + (x + 4)^2
c) (-x + 5)(x - 2) + (x - 7)(x + 7) = (3x + 1)^2 - (3x - 2)(3x + 2)
d) (5x - 1)(x + 1) - 2(x - 3)^2 = (x + 2)(3x - 1) - (x + 4)^2 + (x^2 - x)
2.Rút gọn :
a) A= 3 (x - 1)^2 - (x + 1)^2 + 2(x - 3)(x + 3) - (2x + 3)^2 - (5 - 20x)
b) B= 5x (x - 7)(x + 7) - x (2x - 1)^2 - (x^3 + 4x^2 - 246x) - 175
c) C = -2x (3x + 2)^2 + (4x + 1)^2 + 2 (x^3 + 8x + 3x - 2 ) - (5 - x)
giải phương trình:
a, 2x-5/x+5=3
b, 2/x-1=6/x+1
c, 2x+1/x-1=5(x-1)/x+1
d, x/x-1 - 2x/x2-1=0
e, 1/x-2 + 3=x-3/2-x
f, x+1/x-2 + x-1/x+2= 2(x2+2)/x2-4
g, x+2/x-2 + 1/x+2=x(x-5)/x2-4
h, 1/x+1 - 5/x+2=15/(x+1)(2-x)
i, x-1/x+2 - x/x-2= 5x-2/4-x2
A= x+3/x-2 + x+2/3-x + x+2/x2-5x+6
B= x/x-1 - 2x/x2-1
C= x/x-5 - 3x/x2-1
D= x+1/x+2 + 3x+2/x2-4
E= 3x2+3x-3/x2+x-2 - x+1/x+2 + x-2/1-x
F= x/x-1 + 3/x+1 - 6x-4/x2-1
G= 2x/x+3 + x/x-3 - 3x2+3/x2-9
H= x+3/x-3 + x/x+3 - x2+9/x2-9
bài 1 rút gọn biểu thức
a) (2x-5)^2-4x(x+3)
b) (x-2)^3 -6(x+4)(x-4)-(x-2)(x^2+2x+4)
c)(x-1)^2-2(x-1)(x+2)+(x+2)^2+5(2x-3)
bài 2 rút gọn biểu thức
a)(2-3x)^2-5x(x-4)+4(x-1)
b)(3-x)(x^2+3x+9)+(x-3)^3
c)(x-4)^2(x+4)-(x-4)(x+4)^2+3(x^2-16)
Bài 2: Tìm x biết:
1,x\(^2\)+4x+4=25
2,(5-2x)\(^2\)-16=0
3,(x-3)\(^3\)-(x-3)(x\(^2\)+3x+9)+9(x+1)\(^2\)=15
4,3(x+2)\(^2\)+(2x-1)\(^2\)-7(x-3)9x+3)=36
5,(x-3)(x\(^2\)+3x+9)+x(x+2)(2-x)=1
6,(2x+1)\(^2\)-4(x+2)\(^2\)=9
7,(x+3)\(^{^{ }2}\)-(x-4)(x+8)=1
Tìm x biết:
1> (x+1)^2-(x+2)^2=3
2> (x-1)(x+1)-(x-3)^2=0
3> (x+1)^3-x^2(x+2)-(x-1)^2=0
4> (x+1)(x^2-x+1)-x^2(x+2)+2(x+3)^2=0
