作业帮先化简再求值6a(1-a)-(3a-7)(-3a-7),其中2a+a^2=-2
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/09 15:58:46
先化简再求值6a(1-a)-(3a-7)(-3a-7),其中2a+a^2=-2
先化简再求值6a(1-a)-(3a-7)(-3a-7),其中2a+a^2=-2
先化简再求值6a(1-a)-(3a-7)(-3a-7),其中2a+a^2=-2
6a(1-a)-(3a-7)(-3a-7)
=6a-6a²+(3a)²-49
=3a²+6a-49
=3(a²+2a)-49
=3×(-2)-49
=-55
6a(1-a)-(3a-7)(-3a-7)
=6a-6a²-49+9a²
=3a²+6a-49
=3(a²+2a)-49
=-6-49
=-55