Factorize (20marks)

1. q(p+s)+r(p+s)
2. x(m-7n)+8y(-m+7n)
3. c(11a-1)+d(-11a+b)
4. 5c(a-b)+3d(-a+b)
5. 5p(a-3)+13q(-a+3)
6. p(5-12r)+3q(-5+12r)

2007-05-21 18:39:53 補充：
Corrections:1. pq qs pr rs=q(p s) r(p s)=(p s)(q r)2.mx - 7nx - 8my 56ny=x(m-7n)-8y(m-7n)=(m-7n)(x-8y)3. 11ac - 1c -11ad bd=c(11a-1)-d(11a-b)4. 5ac - 5bc - 3ad 3bd=5c(a-b)-3d(a-b)=(a-b)(5c-3d)

2007-05-21 18:40:00 補充：
5.5ap - 15p - 13aq 39q=5p(a-3)-13q(a-3)=(a-3)(5p-13q)6. 5p - 12pr - 15q 36qr=p(5-12r)-3q(5-12r)=(5-12r)(p-3q)

2007-05-21 18:45:07 補充：
樓下:看清楚題目, 唔好因為做唔到好答案就推算條題目。係: " 11ac - 1c -11ad bd "不是11ac - bc -11ad bd

1.pq + qs + pr + rs
=p(r+s)+q(r+s)
=(p+q)(r+s)
__________________________________________________
2. mx - 7nx - 8my + 56ny
=x(m-7n)-8y(m-7n)
=(x-8y)(m-7n)
__________________________________________________
3. 11ac - bc -11ad + bd
=c(11a-b)-d(11a-b)
=(11a-b)(c-d)
__________________________________________________
4. 5ac - 5bc - 3ad + 3bd
=5c(a-b)-3d(a-b)
=(5c-3d)(a-b)
__________________________________________________
5. 5ap - 15p - 13aq + 39q
=5p(a-3)-13q(a-3)
=(5p-13q)(a-3)
__________________________________________________
6. 5p - 12pr - 15q + 36qr
=p(5-12r)-3q(5-12r)
=(p-3q)(5-12r)
__________________________________________________

1.pq + qs + pr + rs

=p(r+s)+q(r+s)

=(p+q)(r+s)

2. mx - 7nx - 8my + 56ny

=x(m-7n)-8y(m-7n)

=(x-8y)(m-7n)

3. 11ac - bc -11ad + bd

=c(11a-b)-d(11a-b)

=(11a-b)(c-d)

4. 5ac - 5bc - 3ad + 3bd

=5c(a-b)-3d(a-b)

=(5c-3d)(a-b)

5. 5ap - 15p - 13aq + 39q

=5p(a-3)-13q(a-3)

=(5p-13q)(a-3)

6. 5p - 12pr - 15q + 36qr

=p(5-12r)-3q(5-12r)

=(p-3q)(5-12r)