minh lam 2 cau dau da nhe , khi nao co de dung lam tiepko ghi lai de nha1.(x-1)(x+6)(x+2)(x+3)+32=(x^2+5x-6)(x^2+5x+6)+32=(x^2+5x)^2-36+32=(x^2+5x)^2-4=(x^2+5x-2)(x^2+5x+2)2.(a+1)(a+4)(a+2)(a+3)+1=(a^2+5x+4)(a^2+5x+6)+1=(a^2+5x+5-1)(a^2+5x+5+1)+1=(a^2+5x+5)^2-1+1=(a^2+5x+5)^24ban tu nhan da thuc nhe , ket qua la tung nayx^4+4x^3+13x^2+18x+20=x^4+2x^3+2x^3+5x^2+4x^2+4x^2+10x+8x+20=(x^4+2x^3+5x^2)+(2x^3+4x^2+10x)+(4x^2+8x+20)=x^2(x^2+2x+5)+2x(x^2+2x+5)+(4(x^2+2x+5)=(x^2+5x+5)(x^2+2x+4)
minh lam 2 cau dau da nhe , khi nao co de dung lam tiepko ghi lai de nha1.$(x-1)(x+6)(x+2)(x+3)+32$$=(x^2+5x-6)(x^2+5x+6)+32$$=(x^2+5x)^2-36+32$$=(x^2+5x)^2-4$$=(x^2+5x-2)(x^2+5x+2)$2.$(a+1)(a+4)(a+2)(a+3)+1$$=(a^2+5x+4)(a^2+5x+6)+1$$=(a^2+5x+5-1)(a^2+5x+5+1)+1$$=(a^2+5x+5)^2-1+1$$=(a^2+5x+5)^2$$4$ban tu nhan da thuc nhe , ket qua la tung nay$x^4+4x^3+13x^2+18x+20$$=x^4+2x^3+2x^3+5x^2+4x^2+4x^2+10x+8x+20$$=(x^4+2x^3+5x^2)+(2x^3+4x^2+10x)+(4x^2+8x+20)$$=x^2(x^2+2x+5)+2x(x^2+2x+5)+(4(x^2+2x+5)$$=(x^2+5x+5)(x^2+2x+4)$