HKCEE - 2006 - Paper 1 -

Ans: (a) $b(3-a)$ (b) $(3+a)(3-a)$ (c) $(3-a)(3+a+b)$

1. $\b

Ans: A
$\begin{array}{cl}
& pr+qr -ps-qs \
= & r

Ans: B
I is not an identity. For $x=1$,

$\begin{array}{rcl}

Ans: (a) $(r+5{)}^2$ (b) $(r+s+5)(r-s+5)$

1. $\begin{array}{

Ans: A
$\begin{array}{cl}
& (x+x)(y+y+y) \
= &

Ans: C
I has $x+y$ as a factor.

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

II cann

Ans: (a) $ab(a+b)$ (b) $(a+b)(ab+7)$

1. $\begin{array}{cl}

Ans: A
$\begin{array}{cl}
& (3x-5)(2x^2 + 5x -3) \
= &

Ans: (a) $(m+6n{)}^2$ (b) $(m+6n+5k)(m+6n-5k)$

1. $\begin{ar

Ans: B
$\begin{array}{cl}
& ab+ac-a^2-bc \
= &

Ans: (a) $(9m+n)(9m-n)$ (b) $(9m-n)(9m+n+2)$

1. $\begin{ar

Ans: D
$\begin{array}{cl}
& (x-2y)(x+2y-2) \
=