我想問兩條數![急要!20分〕

1a)設菊花和普洱的售價分別是x和y
6x+10y=600(1)
35x=25y(2)
由(2),35x=25y
x=5y/7(3)
將(3)代入(1),
6x+10y=600
6(5y/7)+10y=600
30y/7+10y=600
100y/7=600
y=42
將y=42代入(2),
35x=25y
35x=25(42)
x=30
所以菊花和普洱的售價分別是$30和$42

b)6kg菊花的售價是30x6
=$180

2)設x=1/a和y=1/b
1/a+2/b=-2 (1)
x+y=-2
1/a-3/b=8(2)
x-3y=8
由(2)，x-3y=8(3)
x=8+3y
將x=8+3y代入(1)，
x+y=-2
8+3y+y=-2
y=-2.5
將y=-2.5代入(1)，
x+y=-2
x-2.5=-2
x=0.5
由於x=1/a和y=1/b
所以：0.5=1/a
a=2
y=1/b
-2.5=1/b
b=-0.4

1a) 假設菊花1kg的售價 = x
普洱1kg的售價 = y

6x + 10 y = 600--(1)
35x = 25y -- (2)
From (1)
10y = 600 - 6x
y = 60 - 0.6x
Sub into (2)
35x = 25(60 - 0.6x)
35x + 15x = 1500
x = 30
y = 42

所以菊花1kg的售價 = $30
普洱1kg的售價 = $42

b) 6kg菊花的售價是 6 x 30 = $180

2a) x=1/a和y=1/b
1/a+2/b=-2 --> x + 2y = -2 --(1)
1/a-3/b=8 --> x - 3y = 8 --(2)
From (2) x = 8 + 3y
Sub into (1)
8 + 3y + 2y = -2
5y = -10
y = -2
x = 8 + 3(-2) = 2
a = 1/x =1/2
b = 1/y = -1/2

1A.
Let菊花be X
普洱 be Y
6X+10Y=600---(1)
35X=25Y---(2)
Expand (1)...
(1)x5
30X+50Y=3000
because 35X=25Y
so 30X+70X=3000
100X=3000
X=30

Sub. result of X into (1)
180+10Y=600
10Y=420
Y=42

1B
6KG菊花=6x30=$180


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1/a+2/b=-2
{
1/a-3/=8

呢條唔夠時間...遲d補番

1. let x be the price of 菊花
35x/25=普洱

6x+10(35x/25)=600 solve for x and you can get the answers


2. let x =price of 菊花 , y =price of 普洱

equation 1. 6x+10y=600

equation 2 35x=25y


from 1 x=(600-10y)/6

substitute x into equation 2,

35(600-10y)/6=25y solve for y, then you can work out x

設普洱價錢是a
菊花價錢是5/7a

The equation is: 5/7(6)a+10a=600
than we can time 7 in all parts: 5(6)a+70a=4200
Solve it:
30a+70a=4200
100a=4200
a=42
普洱的價錢是$42/kg and 菊花價錢是$42x5/7=$30/kg


But i don't know how to do 2