F.2 maths

1)
(2x-1 / 3-x) - (1-2x / x-3)
=(2x-1 / 3-x) - (2x-1 / 3-x)
=0

2)
ax+ay = 0
ay = -ax
y = -(ax/a)
y = -x

3)
a = xy / x-y
a(x-y) = xy
ax - ay - xy = 0
x(a-y) = ay
x = ay / a-y

4)
2/p = 1/a + 1/q
2/p = (q+a) / aq
2aq = p(a+q)
2aq - pa - pq = 0
a(2q-p) = pq
a = pq / (2q-p)

5)
p = 4x+1
p = 4(5y+3) + 1
= 20y + 12 + 1
= 20y + 13

6)
p = (Q+2)(3Q-1)
= (2x-1+2)(6x-3-1)
= (2x+1)(6x-4)
= 12x square - 2x - 4

2007-09-29 22:52:27 補充：
上面果個人答的第三條是錯的！！！我才是對的！！！

(1).(2x-1/3-x)-(1-2x/x-3)
=(2x-1/3-x)-(2x-1/x-3)
=0

(2).ax+ay=0
a(x+y)=0
a=0

(3).a=xy/x-y
a(x-y)=xy
ax-ay=xy
ax-xy=ay
x(a-y)=ay
X=ay/a-y

(4).2/p=1/a+1/q
2/p+1/q=1/a
2q+p/pq=1/a
a=pq/2q+p

(5).p=4x+1 and x=5y+3
p=4(5y+3)+1
p=20y+13

(6).p=(Q+2)(3Q-1) and Q=2x-1
p=3Q^2+5Q-2
p=3 (2x-1)^2+5(2x-1)-2
p=3(4x^2-4x+1)+10x-5-2
p=12x^2-2x-4

我諗我唔會錯掛.....he!!

2007-09-29 22:56:44 補充：
改返第2題....sor(2).ax+ay=0a(x+y)=0x+y=0y=-x