F.2 Maths Question

1)x^2-2x-y^2+1
=(x^2-2x+1)-y^2
=(x-1)^2-y^2
=(x-1-y)(x-1+y)

2)16-x^2-2xy-y^2
=16-(x^2+2xy+y^2)
=4^2-(x+y)^2
=(4-x-y)(4+x+y)

3)4(3x-2)^2-9(2x+3)^2
=4(9x^2-12x+4)-9(4x^2+12x+9)
=36x^2-48x+16-36x^2-108x-81
=-156x-65
=-13(12x+5)

4)4x(4x-1)+6x(7-3x)-7(6x+6)-8x+32
=16x^2-4x+42x-18x^2-42x-42-8x+32
=-2x^2-12x-10
=-2(x^2+6x+5)
=-2(x+1)(x+5)

1) If a=1-x^2 and 6=1+x, express a in terms of b.
a=1-x^2
a=(1+x)(1-x)
=b(1-x)

2009-05-17 19:03:34 補充：
6=1+x --> i think your "6" is "b"