已知2x²+xy=M,3y²+2xy=N,求4x²+8xy+9y²

问题描述:

已知2x²+xy=M,3y²+2xy=N,求4x²+8xy+9y²

4x²+8xy+9y²
=4x²+2xy+6xy+9y²
=2(2x²+xy)+3(3y²+2xy)
=2M+3N

慢慢接

4x²+8xy+9y²
=2(2x²+xy)+3(3y²+2xy)
=2M+3N