Phân tích đa thức thành nhân tử :
x4 + x2y2 + y4
Giúp mình với ạ TT
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(4\left(x^2y^2+z^2t^2+2xyzt\right)-\left(x^2+y^2-z^2-t^2\right)^2\)
\(=\left(2xy-2tz\right)^2-\left(x^2+y^2-z^2-t^2\right)\)
\(=\left(2xy-2tz-x^2-y^2+z^2+t^2\right)\left(2xy-2tz+x^2+y^2-z^2-t^2\right)\)
\(=\left[-\left(x-y\right)^2+\left(z-t\right)^2\right]\left[\left(x+y\right)^2-\left(t+z\right)^2\right]\)
\(=-\left(x-y-z+t\right)\left(x-y+z-t\right)\left(x+y-t-z\right)\left(x+y+t+z\right)\)
4(x2y2+z2t2+2xyzt)−(x2+y2−z2−t2)24(x2y2+z2t2+2xyzt)−(x2+y2−z2−t2)2
=[2(xy+zt)]2−(x2+y2−z2−t2)2=[2(xy+zt)]2−(x2+y2−z2−t2)2
=(2xy+2zt)2−(x2+y2−z2−t2)2=(2xy+2zt)2−(x2+y2−z2−t2)2
=(2xy+2zt−x2−y2+z2+t2)(2xy+2zt+x2+y2−z2−t2)2
\(A=\left(x+1\right)\left(x-4\right)\left(x+2\right)\left(x-8\right)+4x^2\)
\(A=\left[\left(x+1\right)\left(x-8\right)\right]\left[\left(x-4\right)\left(x+2\right)\right]+4x^2\)
\(A=\left(x^2-7x-8\right)\left(x^2-2x-8\right)+4x^2\)
Đặt \(p=x^2-4,5x-8\)ta có :
\(A=\left(p-2,5x\right)\left(p+2,5x\right)+4x^2\)
\(A=p^2-\left(2,5x\right)^2+4x^2\)
\(A=p^2-6,25x^2+4x^2\)
\(A=p^2-2,25x^2\)
\(A=p^2-\left(1,5x\right)^2\)
\(A=\left(p-1,5x\right)\left(p+1,5x\right)\)
Thay \(p=x^2-4,5x-8\)vào A ta có :
\(A=\left(x^2-4,5x-8-1,5x\right)\left(x^2-4,5x-8+1,5x\right)\)
\(A=\left(x^2-6x-8\right)\left(x^2-3x-8\right)\)
\(\left(x+1\right)\left(x-4\right)\left(x+2\right)\left(x-8\right)+4x^2\)
\(=\left(x+1\right)\left(x-8\right)\left(x-4\right)\left(x+2\right)+4x^2\)
\(=\left(x^2-7x-8\right)\left(x^2-2x-8\right)+4x^2\)
Đặt \(x^2-2x-8=t\)
Ta có : \(\left(t-5x\right)t+4x^2\)
\(=t^2-5xt+4x^2\)
\(=t^2-2.\frac{5}{2}xt+\frac{25}{4}x^2-\frac{9}{4}x^2\)
\(=\left(t-\frac{5}{2}\right)^2-\frac{9}{4}x^2\)
\(=\left(t-\frac{5}{2}-\frac{3}{2}x\right)\left(t-\frac{5}{2}+\frac{3}{2}x\right)\)
Học tốt ~~
\(x^5-x^4-30x^3=x^3\left(x^2-x-30\right)=x^3\left(x-6\right)\left(x+5\right)\)
\(=\left(x^6+2x^5+x^4\right)-2\left(x^5+2x^4+x^3\right)+2\left(x^4+2x^3+x^2\right)\)
\(=x^2\left(x^2+x\right)^2-2x\left(x^2+x\right)^2+2\left(x^2+x\right)^2\)
\(=\left(x^2+x\right)^2\left(x^2-2x+2\right)\)
\(=x^2\left(x+1\right)^2\left(x^2-2x+2\right)\)
\(\left(2x^2\right)^2+2.2x^2.9+81-\left(6x\right)^2=\left(2x^2+9\right)-\left(6x\right)^2=\left(2x^2+6x+9\right)\left(2x^2-6x+9\right)\)
\(x^4+6x^3+11x^2+6x+1\)
\(=x^4+3x^3+x^2+3x^3+9x^2+3x+x^2+3x+1\)
\(=\left(x^2+3x+1\right)^2\)
\(x^4+6x^3+7x^2-6x+1\)
\(=x^4-2x^2+1+6x^3+9x^2-6x\)
\(=\left(x^2-1\right)^2+6x\left(x^2-1\right)+9x^2\)
\(=\left(x^2+3x-1\right)^2\)
\(=\left(x^4+x^3+x^2\right)+\left(x^2+x+1\right)\)
\(=x^2\left(x^2+x+1\right)+\left(x^2+x+1\right)\)
\(=\left(x^2+1\right)\left(x^2+x+1\right)\)
\(x^4+x^3+2x^2+x+1\)
\(=x^4+x^3+x^2+x^2+x+1\)
\(=\left(x^2+x+1\right)\left(x^2+1\right)\)
\(x^4+x^2y^2+y^4\)
\(=x^4+2x^2y^2+y^4-x^2y^2\)
\(=\left(x^2+y^2\right)^2-\left(xy\right)^2\)
\(=\left(x^2+y^2-xy\right)\left(x^2+y^2+xy\right)\)