5a²-3a²+3(a²-b²)-2(5a²+2b²)怎么合并同类项?

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5a²-3a²+3(a²-b²)-2(5a²+2b²)怎么合并同类项?
5a²-3a²+3(a²-b²)-2(5a²+2b²)怎么合并同类项?

5a²-3a²+3(a²-b²)-2(5a²+2b²)怎么合并同类项?
5a²-3a²+3(a²-b²)-2(5a²+2b²)
=5a²-3a²+3a²-3b²-10a²-4b²
=(5-3+3-10)a²-(3+4)b²
=-5a²-7b²

先把3和5分别乘进去,得:5a²-3a²+3a²-3b²-10a²-4b²
把同类项合并也就是:(5a²-3a²+3a²-10a²)-(3b²+4b²)
=-5a²-7b²