\(a,\left(x-2\right)\left(x+2\right)\left(x^2-10\right)-72\)
\(=\left(x^2-4\right)\left(x^2-10\right)-72\)
\(=x^4-14x^2+40-72\)
\(=x^4-14x^2-32\)
\(=x^4-16x^2+2x^2-32\)
\(=\left(x^2-16\right)\left(x^2+2\right)\)
\(=\left(x-4\right)\left(x+4\right)\left(x^2+2\right)\)
\(b,x^8+x^6+x^4+x^2+1\)
\(=x^8+x^7+x^6+x^5+x^4-x^7-x^6-x^5-x^4-x^3+x^6+x^5+x^4+x^3+x^2-x^5-x^4-x^3-x^2-x+x^4+x^3+x^2+x+1\)
\(=x^4\left(x^4+x^3+x^2+x+1\right)-x^3\left(x^4+x^3+x^2+x+1\right)+x^2\left(x^4+x^3+x^2+x+1\right)-x\left(x^4+x^3+x^2+x+1\right)+\left(x^4+x^3+x^2+x+1\right)\)
\(=\left(x^4+x^3+x^2+x+1\right)\left(x^4-x^3+x^2-x+1\right)\)
\(c,\left(x+y\right)^4+x^4+y^4\)
\(=x^4+4xy^3+6x^2y^2+4x^3y+y^4+x^4+y^4\)
\(=2x^4+2y^4+4xy^3+4x^3y+6x^2y^2\)
\(=2\left(x^4+y^4+2xy^3+2x^3y+3x^2y^2\right)\)
\(=2\left(x^2+y^2+xy\right)^2\)
\(d,\left(x+1\right)^4+\left(x^2+x+1\right)^2\)
\(=x^4+4x^3+4x+6x^2+1+x^4+x^2+1+2x^3+2x+2x^2\)
\(=2x^4+6x^3+9x^2+6x+2\)
\(=2x^4+2x^3+x^2+4x^3+4x^2+2x+4x^2+4x+2\)
\(=x^2\left(2x^2+2x+1\right)+2x\left(2x^2+2x+1\right)+2\left(2x^2+2x+1\right)\)
\(=\left(2x^2+2x+1\right)\left(x^2+2x+2\right)\)
nhờ mn là giúp mình với ạ , minh đang cần gấp :( 
