∵x^3+7x^2-11x+4
=x³+5x²+2x²+10x-21x-105+109
=x²(x+5)+2x(x+5)-21(x+5)+109
=(x+5)(x²+2x-21)+109
∴x^3+7x^2-11x+4除以x+5 得：商是x²+2x-21,余数是109