5X^4+4X^3+3X^2+2X+1
=5x³(x+2)-6x³+3x²+2x+1
=5x³(x+2)-6x²(x+2)+15x²+2x+1
=5x³(x+2)-6x²(x+2)+15x(x+2)-28x+1
=5x³(x+2)-6x²(x+2)+15x(x+2)-28(x+2)+55
∴5X^4+4X^3+3X^2+2X+1除以X+2所得的余数是55
5X^4+4X^3+3X^2+2X+1
=5x³(x+2)-6x³+3x²+2x+1
=5x³(x+2)-6x²(x+2)+15x²+2x+1
=5x³(x+2)-6x²(x+2)+15x(x+2)-28x+1
=5x³(x+2)-6x²(x+2)+15x(x+2)-28(x+2)+55
∴5X^4+4X^3+3X^2+2X+1除以X+2所得的余数是55