唔識做功課2

你想做d咩先-.-

p^2-(p+q)^2
=-2pq-q^2
=q(-2p-q)

2-18(a+1)^2
=-2[9(a+1)^2-1]
=-2[3(a+1)-1][3(a+1)+1]
=-2(3a+2)(3a+4)


我估計係因式分解,
係咪呢D???

2012-09-17 19:26:28 補充：
16x^4-1
=(4x^2+1)(4x^2-1)
=(4x^2+1)(2x+1)(2x-1)