已知m^2-n=45,4m^2+6n+2/3=0,求2m^4+m^2n-3n^2的值.
问题描述:
已知m^2-n=45,4m^2+6n+2/3=0,求2m^4+m^2n-3n^2的值.
答
2m^4+m^2n-3n^2=(m^2-n)(2m^2+3n)
=45*(-1/3)=-15
答
2m^4+m^2n-3n^2=(2m^2+3n)(m^2-n)
已知:m^2-n=45,4m^2+6n+2/3=0
所以:m^2-n=45,2m^2+3n=-1/3
2m^4+m^2n-3n^2=(2m^2+3n)(m^2-n)=-1/3*45=-15