1. (2x - 3) . (2x+3) - 4 . (x+ 2)2 = 6
[ ( 2x )2 - 32 ] - 4 . ( x2 + 2.x.2 + 22) = 6
4x2 - 9 - 4 . ( x2 + 4x + 4) = 6
4x2 - 9 - 4x2 - 16x - 16 = 6
-16x -25 = 6
x = \(-\dfrac{31}{16}\)
Chứng minh biểu thức không phụ thuộc x :
1, \(\left(3x-1\right)^2-2\cdot\left(2x-3\right)\cdot\left(2x+3\right)-\left(x-3\right)^2\)
2, \(\left(3x+2\right)^3-\left(3x-2\right)^3-3\cdot\left(6x-1\right)\cdot\left(6x+1\right)\)
3, \(\left(3x-5\right)^2+3\cdot\left(x+1\right)\cdot\left(x-1\right)-\left(4x-3\right)^2+\left(2x+2\right)\cdot\left(2x+1\right)\)
Tìm x :
a, \(4x^2-\left(3x+1\right)\cdot\left(2x-1\right)=2\cdot\left(x-3\right)^2\)
b.\(\left(5x-1\right)\cdot\left(x+1\right)-\left(2x-1\right)\cdot\left(2x+1\right)=x\cdot\left(x+1\right)\)
c, \(7x^2-\left(2x-3\right)^2=1+3\cdot\left(x+2\right)^2\)
Chứng minh giá trị biểu thức không phụ thuộc x :
1, \(\left(2x+1\right)^3-\left(2x-1\right)^3-2\cdot\left(4x+3\right)^2+8\cdot\left(x+3\right)^2\)
2,\(\left(2x+1\right)^2\cdot\left(x-1\right)-2\cdot\left(x-2\right)^3+x\cdot\left(3-2x\right)\cdot\left(3+x\right)-\left(3x-3\right)^2\)
Chứng minh biểu thức không phụ thuộc x :
\(\left(2x+1\right)^2\cdot\left(x-1\right)-2\cdot\left(x-2\right)^3+x\cdot\left(3-2x\right)\cdot\left(3+x\right)-\left(3x-3\right)^2\)
Tìm x :
a, \(\left(2x+1\right)^2-3x^2+4=\left(1-x\right).\left(1+x\right)\)
b, \(\left(4x-3\right)\cdot\left(4x+3\right)-2\cdot\left(x+2\right)^2=14x^2\)
c, \(\left(2x-1\right)\cdot\left(x+1\right)-x^2+1=\dfrac{1}{2}\cdot\left(x-1\right)^2\)
A=\(3\cdot\left(x-1\right)^2-\left(x+1\right)^2+2\cdot\left(x-3\right)\left(x+3\right)-\left(2x+3\right)^2-\left(5-20x\right)\)
Phân tích thành nhân tử ;
1, \(\left(x+2\right)\cdot\left(x+3\right)\cdot\left(x+4\right)\cdot\left(x+5\right)-24\)
2, \(x\cdot\left(x+4\right)\cdot\left(x+6\right)\cdot\left(x+10\right)+128\)
3, \(\left(x^2+5x+6\right)\cdot\left(x^2-15x+56\right)-144\)
4, \(\left(x-18\right)\cdot\left(x-7\right)\cdot\left(x+35\right)\cdot\left(x+90\right)-67x^2\)
5, \(\left(x-2\right)\cdot\left(x-3\right)\cdot\left(x-4\right)\cdot\left(x-6\right)-72x^2\)
Chứng minh biểu thức không phụ thuộc x :
1, \(\left(2x+1\right)^3-\left(2x-1\right)^3-2\cdot\left(4x+3\right)^2+8\cdot\left(x+3\right)^2\)
B=\(-x\cdot\left(x+2\right)^2+\left(2\cdot x+x\right)^2+\left(x+3\right)\left(x^{ }2-3\cdot x+9\right)-1\)