f(-1)=p-1
p(p-1+1)^2 +q=p-1
做乜鬼呀~~
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既然 f(x)=p(x+1)^2 +q
f(-1)=p-1
p(-1+1)^2 +q=p-1
p(0)+q=p-1 ..................(1)
f(x)=p(x+1)^2 +(p-1)
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f(1)=9
p(1+1)^2 +(p-1)=9
4p+p-1=9
4p+p=10
p=2 ..................(2)
put (2) in (1)
q=2-1
q=1
嘩~~眨下眼十幾年 , 我都唔知自己有無計錯~~