已知实数a、b分别是方程2x^2-6x+3=0的2个根,求2a^3-6a^2+2a^2b-6ab的值?
韦达定理:
a+b=-(-6/2)=3,
ab=3/2,
2a^3-6a^2+2a^2b-6ab
=2a^3+2a^2b-6a^2-6ab
=2a²(a+b)-6a²-6ab
=2a²*(3)-6a²-6*(3/2)
=6a²-6a²-9
=-9
已知实数a、b分别是方程2x^2-6x+3=0的2个根,求2a^3-6a^2+2a^2b-6ab的值?
韦达定理:
a+b=-(-6/2)=3,
ab=3/2,
2a^3-6a^2+2a^2b-6ab
=2a^3+2a^2b-6a^2-6ab
=2a²(a+b)-6a²-6ab
=2a²*(3)-6a²-6*(3/2)
=6a²-6a²-9
=-9