若代数式x2-kx+9是完全平方式，则k的值为______．
∵x2-kx+9=x2-kx+32，
∴kx=±2×3x，
解得k=±6．
故答案为：±6．
——Will you please help me with my English——( )．
A．Excuse me，I'm afraid not
B．It's very nice of you
C．I'm sorry to hear that
D．Certainly，I'll be glad to
活化剂药剂种类有哪些？对哪些矿物有活化作用？
