计算:① -3(2x²-xy)-4(x²-xy-6) ②5a²-[(5a²-2a)-2(a²-3a)]

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计算:①-3(2x²-xy)-4(x²-xy-6)②5a²-[(5a²-2a)-2(a²-3a)]计算:①-3(2x²-xy)-4(x

计算:① -3(2x²-xy)-4(x²-xy-6) ②5a²-[(5a²-2a)-2(a²-3a)]
计算:① -3(2x²-xy)-4(x²-xy-6) ②5a²-[(5a²-2a)-2(a²-3a)]

计算:① -3(2x²-xy)-4(x²-xy-6) ②5a²-[(5a²-2a)-2(a²-3a)]
① -3(2x²-xy)-4(x²-xy-6)
=-6x²+3xy-4x²+4xy+24
=-10x²+7xy+24


②5a²-[(5a²-2a)-2(a²-3a)]
=5a²-(5a²-2a-2a²+6a)
=5a²-(3a²+4a)
=5a²-3a²-4a
=2a²-4a

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