if b,c,d are constants and x2+bx+c=(x+d)2, for all values of x, what is the value of c?
(1)d=3
(2)b=6
答案是D
我选的A, 当x=0时,c=d2=9
不知道为什么单独知道b的值可以求出c
请大家给我点帮助吧
b=6 means d=6 too due to x^2+bx+c=x^2+dx+d^2
we can conclude that d=b,so we need to find out what is the number
about b or d
so the information which tell us that b=6 can sovle the problem
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