我唔識做中一代數

1a)3x+2y+y
=3x+3y
=3(x+y)
1b) 4x-x+2x
=3x+2x
=5x
1c) a+b+b+a
=2a+2b
=2(a+b)
2a)5乘y-2除y
=5y-2/y
=5y^2/y-2/y
=(5y^2-2)/y
2(b) (p除q)乘2
=2p/q
2(c) a-5b乘8除10c
=a-40b/10c
=a-4b/c
=(ac-4b)/c
3(a)2y乘y乘y
=2y^3
3(b) 3x乘2y乘y
=6xy^2
3(c) a乘a^2
=a^3


4文迪有2x張二十元紙幣和3y五十元紙幣,問

(a)他共有紙幣多少張
(2x+3y)張
(b)他共有款項多少?
2x*20+3y*50
=40x+150y
=$10(4x+15y)

5(a)2x+1 [x=3]

當x=3時,代數式的值
=2( 3)+1
=( 7)

5(b)6-x/4 [x=20]

當x=20時,代數式的值
=6-(20)/4
=1

6(a)6x-5 [x=-2]
6(-2)-5
=-17

6(b)2x/x+7 [x=-1]
2(-1)/(-1)+7
=9



7(a)4m-6n [m=3,n=-5]

當m=3和n=-5時,代數式的值

4(3)-6(-5)
=42

7(b)m^2-2n^2 [m=-5,n=3]
=(-5)^2-2(3)^2
=25-2*9
=7

8(a)假設c=60n+1200,若n=3,求c的值
c=60(3)+1200
c=1380

8(b)假設h=21/t-t,若t=-3,求h的值
h=21/(-3)-(-3)
h=-7+3
h=-4

9(a)已知公式a=n/2(3d-1),假設n=6和d=1/2,求a的值
a=(6)/2[3(1/2)-1]
a=12(1/2)
a=6

9(b)已知公式s=u^2-(v+1)^2,假設u=4和v=2,求s的值
s=(4)^2-[(2)+1]^2
s=16-9
s=7



㊣HOPE THEY CAN HELP YOU!!!!㊣

1(a) 3y+2y+1y
= 6y

1(b) 4x-x+2x
= 5x

1(c) a+b+b+a
= 2a+2b

2(a)5乘y-2除y
= 5y - 2/y
= 5y^2/y - 2/y
= (5y^2 - 2)/y

2(b) (p除q)乘2r
= 2pr/q

2(c) a-5b乘8除10c
= (8a - 40b)/10c
= (4a - 20b)/5c

3(a) 2y乘y乘y
= 2y^3

3(b) 3x乘2y乘y
= 6xy^2

3(c) a乘a^2
= a^3

4文迪有2x張二十元紙幣和3y五十元紙幣,問

(a)他共有紙幣多少張
= 2x + 3y

(b)他共有款項多少?
= (2X * 20) + (3y * 50)
= 40x + 150y

5(a) 2x+1 [x=3]
=2(3)+1
=(7)

5(b) 6-x/4 [x=20]
=6-(20)/4
= -7/2
= -3.5

6(a) 6x-5 [x=-2]
= 6(-2) - 5
= -17

6(b) 2x/x+7 [x=-1]
= 2(-1) / (-1)+7
= -2/6
= -1/3

7(a) 4m-6n [m=3,n=-5]
= 4(3) - 6(-5)
= 12 + 30
= 42

7(b) m^2-2n^2 [m=-5,n=3]
= (-5)^2 - 2(3)^2
= 25 - 18
= 7

8(a) 假設c=60n+1200,若n=3,求c的值
c = 60(3) + 1200
c = 180 + 1200
c = 1380

8(b)假設h=21/t-t,若t=-3,求h的值
唔知你有無打錯題目 , 如果無打錯唔使計都知 h = 0

9(a)已知公式a=n/2(3d-1),假設n=6和d=1/2,求a的值
a= 6/2 [3(1/2)-1]
a= 3 (3/2 - 2/2)
a= 3/2
a = 1.5

9(b)已知公式s=u^2-(v+1)^2,假設u=4和v=2,求s的值
s = (4)^2 - (2+1)^2
s = 16 - 9
s = 7