`(x-2)^3-x(x-2)(x+2)+6x(x-3)`
`=(x^2-3*x^2*2+3*x*2^2-2^3)-x(x^2-4)+6x^2-18x`
`=x^3-6x^2+12x-8-x^3+4x+6x^2-18x`
`=(x^3-x^3)+(6x^2-6x^2)+(12x-18x)-8`
`=-6x-8`
Bài 3: phân tích thành nhân tử:
1/ 9x^3-xy^2
2/x^2-3xy-6x+18y
3/x^2-3xy-6x+18y 3/6x(x-y)-9y^2+9xy
4/ 6xy-x^2+36-9y^2
5/ x^4-6x^2+5
6/ 9x62-6x-y^2+2y
Bài 4:Tìm x, biết:
1/ (x-1)(x^2+x+1)-x^3-6x=11
2/ 16x^2-(3x-4)^2=0
3/ x^3-x^2+3-3x=0
4/ x-1/x+2=x+2/x+1
5/1/x+2/x+1=0
6/ 9-x^2/x : (x-3)=1
Bài5: 1/ 12x^3y^2/18xy^5
2/10xy-5x^2/2x^2-8y^2
3/ x^2-xy-x+y/x^2+xy-x-y
4/ (x+1)(x^2-2x+1)/(6x^2-6)(x^3-1)
5/ 2x^2-7x+3/1-4x^2
Rút gọn:
A=(x^4 - 3x^2 + 9)(x^2 + 3) + (3 - x^2)^2
M= 5(x+2y)^2 - (3y + 2x)^2 + (4x - y)^2 + 3(x - 2y)(x + 2y)
E= (6x + 1)^2 + (6x - 1)^2 - 2(1 + 6x)(6x - 1)
C= (x^2 + 4)(x + 2)(x -2) - (x^2 - 3)^3
Bài 1. Thu gọn:
a) x2 – 4 – (x + 2)2 | b) (x + 2)(x – 2) – (x – 3)(x + 1) |
c) (x – 2)(x + 2) – (x – 2)(x + 5) | d) (6x + 1)2 + (6x – 1)2 – 2(6x + 1)(6x – 1) |
e) 7a(3a – 5) + (2a -3)(4a + 1) – (6a – 2)2 | g) (5y – 3)(5y + 3) – (5y – 4)2 |
h) (3x + 1)3 – (1 – 2x)3 | i) (2x + 1)2 + 2(4x2 – 1) + (2x – 1)2 |
Tìm x Toán đại 8 Hằng đẳng thức đáng nhớ?
Tìm x:
1. (x-1)^3+3.(x-3)^2-(x+2).(x^2-2x+4) = (x+2)^3-(x-3).(x^2+9)-6x^2+5
2.(3+2x)^3-(6x-1).(6x+1) = (2x-1)^3+(x+4)^2-x^3+(x+1).(x^2+x+1)
1, (x-2)(x+2)(x^2+4)-(x^2-3)(x^2+3)
2, (6x+1)^2 +(6x-1)^2 -2(1+6x)(6x-1)
giúp mik với
Bài 3 : Tìm x biết
a) (x-2)^2-x(x-3)=0
b) (x+3)(2x+1)-2(x-1)^2=0
c) (4x-5)^2=9(2-5x)^2
d) X^2-6x-13=0
e) (x+2)(x^2-2x+4)-x(x^2+2)=15
f) X^3-6x^2+12x-19=0
làm phép chia :
a) (x^4 -2x^3 + 2x -1) : (x^2 - 1)
b) (x^3 -8) : (x^2 + 2x +4)
c) (x^6 - 2x^5 + 2x^4 + 6x^3 - 4x^2)n: 6x^2
d) (-2x^5 + 3x^2 - 4x^3) :2x^2
e) (15x^3 - 10x^2 + x - 2) : (x - 2)
f) (2x^4 - 3x^3 - 3x^2 + 6x - 2) : (x^2 - 2)
x-3/x+3 - x+3/x-3= 6x^2/9-6x^2
rút gọn biểu thức
(6x +1) ^2 +(6x-1)^2-2(1+6x)(6x-1)
x(2x^2-3)-x^2(5x+1)+x^2
3x(x-2)-5x(1-x)-8(x^2-3)
rút gọn biểu thức
(6x +1) ^2 +(6x-1)^2-2(1+6x)(6x-1)
x(2x^2-3)-x^2(5x+1)+x^2
3x(x-2)-5x(1-x)-8(x^2-3)
