楼上没看清题目
由根与系数关系得:x1+x2=-1
由已知得:x1^2+x1-3=0,x2^2+x2-3=0
∴x1^2=3-x1,x2^2=3-x2
∴x1^3-4x^2+19
=x1(3-x1)-4(3-x2)+19
=3x1-x1^2-12+4x2+19
=3x1-(3-x1)+4x2+7
=3x1-3+x1+4x2+7
=4(x1+x2)+4
=4×(-1)+4
=0
楼上没看清题目
由根与系数关系得:x1+x2=-1
由已知得:x1^2+x1-3=0,x2^2+x2-3=0
∴x1^2=3-x1,x2^2=3-x2
∴x1^3-4x^2+19
=x1(3-x1)-4(3-x2)+19
=3x1-x1^2-12+4x2+19
=3x1-(3-x1)+4x2+7
=3x1-3+x1+4x2+7
=4(x1+x2)+4
=4×(-1)+4
=0