\(3x^n\left(4x^{n-1}-1\right)-2x^{n+1}\left(6x^{n-2}-1\right)\)
\(=3x^n.4x^{n-1}-3x^n-2x^{n+1}.6x^{n-2}+2x^{n+1}\)
\(=12x^{n+n-1}-3x^n-12x^{n+1+n-2}+2x^{n+1}\)
\(=12x^{2n-1}-3x^n-12x^{2n-1}+2x^{n+1}\)
\(=2x^{n+1}-3x^n\)
\(=2x^n.x-3x^n\)
\(=x^n\left(2x-3\right)\)
Rút gọn biểu thức:
\(3x^n\left(6x^{n-3}+1\right)-2x^n\left(9x^{n-3}-1\right)\)
\(5^{n+1}-4.5^n\)
Tìm x :
\(3x\cdot\left(x-2\right)-2x\cdot\left(2x-1\right)=\left(1-x\right)\cdot\left(1+x\right)\)
\(\left(5x+3\right)\cdot\left(3x-5\right)-\left(x-2\right)\cdot\left(2x+1\right)=6x\cdot\left(3x+1\right)-x^2\)
\(\left(2x-1\right)\cdot\left(2x+1\right)-3\cdot\left(x-1\right)=\left(1-4x\right)\cdot\left(1-x\right)\)
\(\left(2x^2+1\right)\cdot\left(3x^2-1\right)-\left(4x^2-3\right)\cdot\left(x^2+1\right)=x\cdot\left(2x^3+1\right)\)
GIÚP MK ĐI MAI MK PHẢI NỘP RÙI !
Thực hiện phép tính , rút gọn bt
\(\dfrac{2x+y}{2x^2-xy}+\dfrac{16x}{y^2-4x^2}+\dfrac{2x-y}{2x^2+xy}\)
\(\dfrac{x+y}{2\left(x-y\right)}+\dfrac{2}{x^2+3}+\dfrac{1}{x+1}\)
Hãy rút gọn biểu thức:
a) \(\left(3x^{n+1}-y^{n-1}\right)-3\left(x^{n+1}+5y^{n-1}\right)+4\left(x^{n+1}+2y^{n-1}\right)\)
b) \(\left(\dfrac{3}{4}x^{n+1}-\dfrac{1}{2}y^n\right)\times2xy-\left(\dfrac{2}{3}x^{n+1}-\dfrac{5}{6}y^n\right)\times7xy\)
thực hiện phép tính
a/ \(\left(x-2\right)^3-x\left(x+1\right)\left(x-1\right)+6x\left(x-3\right)\)
b/ \(\left(x-2\right)\left(x^2-2x+4\right)\left(x+2\right)\left(x^2+2x+4\right)\)
Chứng tỏ rằng các đa thức sau không phụ thuộc vào biến:
a) \(x\left(2x+1\right)-x^2\left(x+2\right)+\left(x^3-x+3\right)\)
b) \(4\left(x-6\right)-x^2\left(2+3x\right)+x\left(5x-4\right)+3x^2\left(x-1\right)\)
c) \(\left(x^2+2x+3\right)\left(3x^2-2x+1\right)-3x^2\left(x^2+2\right)-4x\left(x^2-1\right)\)
3x^n(4x^n-1)-2x^n+1(6x^n-2-1) =
Tính giá trị biểu thức biết:
\(2x^{n+1}.\left(x^{n-1}-y^{n-1}\right)+y^{n-1}\left(2x^{n+1}-y^{n+1}\right)\)
biết x=-1; y=-1
Tìm x biết:
a) \(\left(3x-1\right)\left(2x+7\right)-\left(x+1\right)\left(6x+5\right)=x+2-\left(x-5\right)\)
b) \(\left(x+1\right)\left(x+2\right)\left(x+5\right)-x^3-8x^2=27\)
