F.2 maths problem

1a) 9y²+30y+16
=(3y+8)(3y+2)

1b) 1/y=(x-1)/(x+1)+1/z [x]
y=(x+1)/(x-1)+z
y-z=(x+1)/(x-1)
(x-1)(y-z)=x+1
xy-xz-y+z=x+1
xy-xz-x-y+z=1
x(y-z-1)=1+y-z
x=(1+y-z)/(y-z-1)

2013-09-29 21:06:57 補充：
9y²+30y+16

用十字相乘法

將頭尾寫成2個數相乘:
9y²=3y*3y
16=8*2

3y ╲ ╱ 8
╳
3y ╱ ╲ 2

交义乘埋再相加:
2(3y)+8(3y)
=6y+24y
=30y
=中間個數

唔明上網查【十字相乘法】啦^^

2013-09-29 21:08:24 補充：
3y ╲ ╱ 8
. . . ╳
3y ╱ ╲ 2

用全形字的空格即成～

皎　　　潔
　＼　／
　　╳
　／　＼
明　　　月

i need steps in first question.