已知3a²—a—4=0,求7+2a—6a²的值
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已知3a²—a—4=0,求7+2a—6a²的值
已知3a²—a—4=0,求7+2a—6a²的值
已知3a²—a—4=0,求7+2a—6a²的值
3a²—a=4
a—3a²=-4
2a-6a²=-4*2=-8
所以:7+2a—6a²=7+(-8)=-1
3a²—a—4=0
3a²—a=4
6a²—2a=8
7+2a—6a²
=7-(6a²—2a)
=7-8
=-1
-1