Toán x^5+x+1 x^5+x^4+1 X^8+X+1 x^8+x^7+1 Phân tích đa thức thành nhân tử 11/09/2021 By Amaya x^5+x+1 x^5+x^4+1 X^8+X+1 x^8+x^7+1 Phân tích đa thức thành nhân tử
1 . x5 + x + 1 = x5 – x2 + x2 + x + 1 = x2( x3 – 1) + ( x2 + x + 1) = x2( x – 1)( x2 + x + 1) + ( x2 + x + 1) = ( x2 + x + 1)( x3 – x2 + 1) 2 . x5 + x4 + 1 = x5 + x4 + x3 – x3 + 1 = x3( x2 + x + 1) – ( x3 – 1) = x3( x2 + x + 1) – ( x – 1)( x2 + x + 1) = ( x2 + x + 1)( x3 – x + 1) 3. x8 + x + 1 = x8 – x2 + x2 + x + 1 = x2( x6 – 1) + ( x2 + x + 1) = x2( x3 – 1)( x3 + 1) + ( x2 + x + 1) = ( x5 + x2)( x – 1)( x2 + x + 1) + ( x2 + x + 1) = ( x2 + x + 1)( x6 – x5 + x3 – x2 + 1) 4. x8 + x7 + 1 = x8 + x7 + x6 – x6 + 1 = x6( x2 + x + 1) – [ ( x3)2 – 1 ] = x6( x2 + x + 1) – ( x3 – 1)( x3 + 1) = x6( x2 + x + 1) – ( x – 1)( x2 + x + 1)( x3 + 1) = ( x2 + x +1 )[ x6 – ( x – 1)( x3 + 1) ] = ( x2 + x +1 )( x6 – x4 – x + x3 + 1) Trả lời
$x^{5}$+x+1=$x^{5}$-$x^{2}$+$x^{2}$+x+1=$x^{2}$($x^{3}$-1)+($x^{2}$+x+1)=$x^{2}$(x-1)($x^{2}$+x+1)+($x^{2}$+x+1)=($x^{2}$+x+1)($x^{3}$-$x^{2}$)+($x^{2}$+x+1)=($x^{2}$+x+1)($x^{3}$-$x^{2}$+1) $x^{5}$+$x^{4}$+1=$x^{5}$-$x^{2}$+$x^{4}$-x+$x^{2}$+x+1=$x^{2}$($x^{3}$-1)+x($x^{3}$-1)+($x^{2}$+x+1)=$x^{2}$(x-1)($x^{2}$+x+1)+x(x-1)($x^{2}$+x+1)+($x^{2}$+x+1)=($x^{2}$+x+1)($x^{3}$-$x^{2}$)+($x^{2}$+x+1)($x^{2}$-x)+($x^{2}$+x+1)=($x^{2}$+x+1)($x^{3}$-$x^{2}$+$x^{2}$-x+1) =($x^{2}$+x+1)($x^{3}$-x+1) $x^{8}$+x+1=$x^{8}$-$x^{5}$+$x^{5}$-$x^{2}$+$x^{2}$+x+1=$x^{5}$($x^{3}$-1)+$x^{2}$($x^{3}$-1)+($x^{2}$+x+1)=$x^{5}$(x-1)($x^{2}$+x+1)+$x^{2}$(x-1)($x^{2}$+x+1)+($x^{2}$+x+1)=($x^{2}$+x+1)($x^{6}$-$x^{5}$)+($x^{2}$+x+1)($x^{3}$-$x^{2}$)+($x^{2}$+x+1)=($x^{2}$+x+1)($x^{6}$-$x^{5}$+$x^{3}$-$x^{2}$+1) $x^{8}$+$x^{7}$+1=$x^{8}$-$x^{5}$+$x^{7}$-$x^{4}$+$x^{5}$-$x^{2}$+$x^{4}$-x+$x^{2}$+x+1=$x^{5}$($x^{3}$-1)+$x^{4}$($x^{3}$-1)+$x^{2}$($x^{3}$-1)+x($x^{3}$-1)+$x^{2}$+x+1=$x^{5}$(x-1)($x^{2}$+x+1)+$x^{4}$(x-1)($x^{2}$+x+1)+$x^{2}$(x-1)($x^{2}$+x+1)+x(x-1)($x^{2}$+x+1)+$x^{2}$+x+1=($x^{2}$+x+1)($x^{6}$-$x^{5}$)+($x^{2}$+x+1)($x^{5}$-$x^{4}$)+($x^{3}$-$x^{2}$)($x^{2}$+x+1)+($x^{2}$-x)($x^{2}$+x+1)+($x^{2}$+x+1) =($x^{2}$+x+1)($x^{6}$-$x^{5}$+$x^{5}$-$x^{4}$+$x^{3}$-$x^{2}$+$x^{2}$-x+1) =($x^{2}$+x+1)($x^{6}$-$x^{4}$+$x^{3}$-x+1) Trả lời
1 . x5 + x + 1
= x5 – x2 + x2 + x + 1
= x2( x3 – 1) + ( x2 + x + 1)
= x2( x – 1)( x2 + x + 1) + ( x2 + x + 1)
= ( x2 + x + 1)( x3 – x2 + 1)
2 . x5 + x4 + 1
= x5 + x4 + x3 – x3 + 1
= x3( x2 + x + 1) – ( x3 – 1)
= x3( x2 + x + 1) – ( x – 1)( x2 + x + 1)
= ( x2 + x + 1)( x3 – x + 1)
3. x8 + x + 1
= x8 – x2 + x2 + x + 1
= x2( x6 – 1) + ( x2 + x + 1)
= x2( x3 – 1)( x3 + 1) + ( x2 + x + 1)
= ( x5 + x2)( x – 1)( x2 + x + 1) + ( x2 + x + 1)
= ( x2 + x + 1)( x6 – x5 + x3 – x2 + 1)
4. x8 + x7 + 1
= x8 + x7 + x6 – x6 + 1
= x6( x2 + x + 1) – [ ( x3)2 – 1 ]
= x6( x2 + x + 1) – ( x3 – 1)( x3 + 1)
= x6( x2 + x + 1) – ( x – 1)( x2 + x + 1)( x3 + 1)
= ( x2 + x +1 )[ x6 – ( x – 1)( x3 + 1) ]
= ( x2 + x +1 )( x6 – x4 – x + x3 + 1)
$x^{5}$+x+1
=$x^{5}$-$x^{2}$+$x^{2}$+x+1
=$x^{2}$($x^{3}$-1)+($x^{2}$+x+1)
=$x^{2}$(x-1)($x^{2}$+x+1)+($x^{2}$+x+1)
=($x^{2}$+x+1)($x^{3}$-$x^{2}$)+($x^{2}$+x+1)
=($x^{2}$+x+1)($x^{3}$-$x^{2}$+1)
$x^{5}$+$x^{4}$+1
=$x^{5}$-$x^{2}$+$x^{4}$-x+$x^{2}$+x+1
=$x^{2}$($x^{3}$-1)+x($x^{3}$-1)+($x^{2}$+x+1)
=$x^{2}$(x-1)($x^{2}$+x+1)+x(x-1)($x^{2}$+x+1)+($x^{2}$+x+1)
=($x^{2}$+x+1)($x^{3}$-$x^{2}$)+($x^{2}$+x+1)($x^{2}$-x)+($x^{2}$+x+1)
=($x^{2}$+x+1)($x^{3}$-$x^{2}$+$x^{2}$-x+1)
=($x^{2}$+x+1)($x^{3}$-x+1)
$x^{8}$+x+1
=$x^{8}$-$x^{5}$+$x^{5}$-$x^{2}$+$x^{2}$+x+1
=$x^{5}$($x^{3}$-1)+$x^{2}$($x^{3}$-1)+($x^{2}$+x+1)
=$x^{5}$(x-1)($x^{2}$+x+1)+$x^{2}$(x-1)($x^{2}$+x+1)+($x^{2}$+x+1)
=($x^{2}$+x+1)($x^{6}$-$x^{5}$)+($x^{2}$+x+1)($x^{3}$-$x^{2}$)+($x^{2}$+x+1)
=($x^{2}$+x+1)($x^{6}$-$x^{5}$+$x^{3}$-$x^{2}$+1)
$x^{8}$+$x^{7}$+1
=$x^{8}$-$x^{5}$+$x^{7}$-$x^{4}$+$x^{5}$-$x^{2}$+$x^{4}$-x+$x^{2}$+x+1
=$x^{5}$($x^{3}$-1)+$x^{4}$($x^{3}$-1)+$x^{2}$($x^{3}$-1)+x($x^{3}$-1)+$x^{2}$+x+1
=$x^{5}$(x-1)($x^{2}$+x+1)+$x^{4}$(x-1)($x^{2}$+x+1)+$x^{2}$(x-1)($x^{2}$+x+1)+x(x-1)($x^{2}$+x+1)+$x^{2}$+x+1
=($x^{2}$+x+1)($x^{6}$-$x^{5}$)+($x^{2}$+x+1)($x^{5}$-$x^{4}$)+($x^{3}$-$x^{2}$)($x^{2}$+x+1)+($x^{2}$-x)($x^{2}$+x+1)+($x^{2}$+x+1)
=($x^{2}$+x+1)($x^{6}$-$x^{5}$+$x^{5}$-$x^{4}$+$x^{3}$-$x^{2}$+$x^{2}$-x+1)
=($x^{2}$+x+1)($x^{6}$-$x^{4}$+$x^{3}$-x+1)