\(\left(x^2-1\right)x\left(x+2\right)-x^2.x\left(x+2\right)=21\)
\(\Leftrightarrow x^4+2x^3-x^2-2x-x^4-2x^3=21\)
\(\Leftrightarrow-x^2-2x-21=0\)
Do : \(-x^2-2x-21=-\left(x^2+2x+1\right)-20=-\left(x+1\right)^2-20\le-20< 0\)
Nên phương trình vô nghiệm !!
Chúc bạn học tốt !!
Tìm x, biết :
a, ( x +2 ) ( x^2 - 2x + 4 ) - x( x + 3 ) ( x - 3) = 26
b, ( x - 3 ) ( x^2 + 3x + 9 ) - x( x - 4 ) ( x + 4 ) = 21
c, ( 2x -1 ) ( 4x^2 + 2x + 1 ) - 4x(2x^2 - 3 ) = 23
Giải phương trình:
n) \(\left|3-x\right|+x^2-x\left(x+4\right)=0\)
m)\(\left(x-1\right)^2+\left|x+21\right|-x^2-13=0\)
e) \(\left|5x\right|=3x-2\)
g)\(\left|-2,5x\right|=x-12\)
h) \(\left|5x\right|-3x-2=0\)
i)\(\left|-2x\right|+x-5x-3=0\)
Xác định các hệ số a, b, c biết rằng: Với mọi giá trị của x thì:
a, (5x-3)(2x-c)=ax2+bx+21
b, (2x+4)(x2+bx-1)=9x3+58x2+ 15x+c
Giúp mẹ nhoa
Tính(rút gọn)
1, x^ 2 - 2x + 5 - (x - 7)(x + 2)
2,-5x(x-5)+(x-3)(x^2-7)
3, x(x^2-x-2)-(x+5)(x-1)
4, (-x+5)(x+3)+(2x-1)(x+3)
5, -4x(x+3)(x-4)-3x(x^2-x+1)
Bài 1:
a) x (\(x^2\) + 2) + 2x\((1-\dfrac{1}{2}x^2)=4\)
b) (2x)\(^2\) (x – 1) + x(\(x^2\) + 4x) = 40
c) 3x(x – 2) – 3(\(x^2\) – 3) = 8
d) 2\(x^2\)(4\(x^3\) + 2x) + (\(x^2\) – 2)(- 2x)\(^3\) = 20
Bài 2:
P = 3x(\(\dfrac{2}{3}\)\(x^2\) − \(3x^4)\) + (3x)\(^2\) (\(x^3\) – 1) + (- 2x + 9)\(x^2\) - 12
Bài 1
1) (x^2-2x+3)*(x-4)
2) (2x^2-3x-1)*(5x+2)
3) (x^2-2xy+y^2)*(y^2+2xy+x^2+1)
4) (x-7)*(x+5)*(x-5)
5) (x+2y)*(x-y)
6) (x+5)*(x^2-2x+3)
7) 2x(x+5)*(x-1)
8) (x-2y)*(x+2y)
9) (x-1)*(x^2+x+1)
10) (1-2x^2+x)*(x-4+x^2)
thực hiện phép tính :
a)2x^2+3(x-1)(x+1)-5x(x+1)
b) (8-5x)(x+2)+4(x-2)(x+1)+2(x-2)(x+2)+10
c) 4(x-1)(x+5)-(x+2)(x+5)-3(x-1)(x+2)
Tìm x, biết:
a) (x-2)(x-1) = x(2x+1)+2
b) (x+2)(x+2) - (x-2)(x-2) = 8x
c) (2x-1)(x2-x+1) = 2x3-3x2+2
d) (x+1)(x2+2x+4) - x3 - 3x2 + 16 = 0
e) (x+1)(x+2)(x+5) - x3- 8x2 = 27
Rút gọn :
1, 2x(x-5)-(x-2)2-(x+3)(x-3)
2, (x+1)2-3(x-5)(x+5)-(2x-1)2
3, (x-1)3-(x-3)(x2+3x+9)
4, (x+5)(x2-5+25)-(x+2)3
5, 2x(x-7)-(x+3)(x-2)2+(x+1)2
6, (2x+5)(x-3)-(x+5)(x-1)-(x-4)2
8, (x+5)(x-5)(x+2)-(x+2)3
