问几道数学题,3(x²-y²)-4(2x²-3y²)怎么做?

问题描述:

问几道数学题,3(x²-y²)-4(2x²-3y²)怎么做?

3(x²-y²)-4(2x²-3y²)
=3x²-3y²-8x²+12y²
=-5x²+9y²