a) (x-2)(2x+3)=0 b) x2-6x+9=0 c)x2-(x+1)2=0
-> x-2=0 hay 2x+3=0 -> (x-3)2=0 x2-(x2+2x+1)=0
-> x=2 hay x=-3/2 -> x-3=0-> x=3 x2-x2-2x-1=0
-2x-1=0
x=-1/2
d)x(2x-4)-2x(x+3)=20 e) 3x(x-4)+12x-48=0
2x2-8x-2x2-6x=20 3x2-12x+12x-48=0
-14x=20 3x2-48=0
x=-10/7 3x2=48
x2=48:3
x2=16-> x=4 hay x= -4
f) 4x2+4x=-1 g) (2x-3)2+(x-3)(2x+3)=0
4x2+4x+1=0 4x2-12x+9+2x2+3x-6x-9=0
(2x+1)2=0 6x2-15x=0
2x+1=0 3x(2x-5)=0
x=-1/2 3x=0 hay 2x-5=0
x=0 hay x=5/2
Bài 1: CMR các đa thức sau luôn dương vs mọi giá trị biến số:
a) x^2 + x +1
b) x^2 + 3x+3
c) x^2 + y^2 + 2(x-2y) +6
d) 2x^2 + y^2 + 2x( y-1) +2
Bài 2: Phân tích thành nhân tử:
a) x^2 + 2x-3
b) x^2 - 10x +9
c) x^2 - 2x -15
d) x^2 - 2x -48
e) x^2 - 10x+24
f)4x^2 + 4x -15
g) 3x^2 - 7x +2
h) 4x^2 - 5x +1
Bài 3: Tìm x biết :
a) x^2 +5x+6=0
b) x^2 - 10x + 16=0
c) x^2 - 10x +21=0
d) x^2 - 2x -3 =0
e) 2x^2 + 7x +3=0
f) x^2 - x- 6=0
Bài 4:
a)x^3 + 2x^2 - 3=0
b) x^3 - 7x -6=0
c) x^3 + x^2 +4=0
d) x^3 - 2x^2 - x+2 =0
lm giups mk vs ạ,mk cảm ơn rất nhiều
Tim x biết
a)2x(x-5)-x(3+2x)=26
b)5x(x-1)=x-1
C)2(x+5)-x^2-5x=0
d)(2x-3)^2(x+5)=0
e)3x^3-48x=0
f)x^3+x^2-4x=0
Tìm x :
a) x ( x - 1 ) - x^2 + 2x = 5
b) 4x ( 3x + 2 ) - 6x ( 2x + 5 ) + 21 ( x - 1 ) = 0
c) 2x( x + 1) - x^2 ( x + 2 ) + x^3 - x + 4 = 0
tìm x biết
a, x(2x-7)-4x+14=0
b, x(x-1)+2x-2=0
c, 2x^3+3x^2+2x+3=0
d, x^3+6x^2+11x+6=0
Tìm x, biết:
a) 4x2-12x=-9
b) (5-2x)(2x+7)=4x2-25
c) x3+27+(x+3)(x-9)=0
d) 4(2x+7)2-9(x+3)2=0
bai1.tim x biet:
a,(x+2).(x+3)-(x-2).(x+5)=0
b,(2x+3).(x-4)+(x-5).(x-2)=(3x-5).(x-4)
c,(8x-3).(3x+2)-(4x+7).(x+4)=(2x+1).(5x-1)=33
Tìm x,biết :
a) 2x^2-7x+5=0
b) x(2x-5) - 4x+10=0
c) (x-5)(x+5) - x(x-2)=15
d) x^2(2x-3) - 12+8x=0
e) x(x - 1)+5x - 5=0
f) (2x-3)^2 - 4x(x - 1)=5
g) x(5 - 2x)+2x(x - 1)=13
h)2(x+5)(2x - 5)+(x - 1)(5 - 2x)=0
bài 2: Tìm x,biết :(cách làm nữa nhé )
a) 9x2 -49=0
b)(x+3)(x2 -3x+9)-x(x-1)(x+1)-27=0
c) (x-1)(x+2)-x-2=0
d)x(3x +2)+( x+1)2 -(2x-5)(2x+5) = 0
e) (4x+1)(x-2)-(2x-3)(2x+1)=7
giai PT
a,(y-1)2=9
b,(x-4)2-25=0
c,(x-3)2-(x-1)2=0
d,(3x-7)2-4(x+1)2=0
e,2x(x-5)-x(2x+3)=26
f,5x(x-1)=x-1
g,x3+2x-3=0
h,x3-5x2+8x-4=0
i,x3-7x+6=0
k,x3-9x2+6x+16=0