将y=(2x-1)•(x+2)+1化成y=a(x+m)2+n的形式为(  ) A.y=2(x+34)2−2516 B.y=2(x−34)2−178 C.y=2(x+34)2−178 D.y=2(x+34)2+178

问题描述:

将y=(2x-1)•(x+2)+1化成y=a(x+m)2+n的形式为(  )
A. y=2(x+

3
4
)2
25
16

B. y=2(x−
3
4
)2
17
8

C. y=2(x+
3
4
)2
17
8

D. y=2(x+
3
4
)2+
17
8

y=(2x-1)(x+2)+1
=2x2+3x-1
=2(x2+

3
2
x+
9
16
)-
9
8
-1
=2(x+
3
4
2-
17
8

故选C.