F.1升F.2嘅Ｍaths題

"解下列各不等式
1.a+2>3
2.3x-4<5 "

1) a+2>3
__a>1

2)3x - 4<5
__3x<9
__x<3

"解下列各方程
-8(x-2)=4-7x
-3(x+3)分2(x-4)=-3"

- 8 (x - 2) = 4 - 7x
- 8x + 16 = 4 - 7x
- 8x + 7x =4 - 16
- x= - 12
x=12

- 3 (x + 3)
-------------- = 3
2 (x - 4)

- 3x - 9
------------ = 3
2x - 8

- 3x - 9 = 3 (2x - 8)
- 3x - 9 = 6x - 24
- 3x - 6x = - 24 +9
- 9x = - 15
x = 5/3 or 1.667

"按x的降冪排列下列各多項式
-3+2x-5x^2
3x^3y-2xy^3+4xx^2-5"

- 3 + 2x - 5x^2
= - 5x^2 + 2x - 3

3x^3y - 2xy^3 + 4xx^2 - 5
=3x^3y - 2xy^3 + 4x^2 - 20
=3x^3y + 4x^2 - 2xy^3 -20

"化簡下列各數式&把它們按x的降冪排列
(2x-3)(x=2y)>>>>>>>>>>>>>應該係(x-2y)？
(2x-3x^2+7)-(4x^2-3x-1)"

(2x - 3) (x - 2y)
=x (2x - 3) - 2y (2x - 3)
=2x^2 - 3x - 4xy + 6y
=2x^2 - 4xy - 3x + 6y

(2x - 3x^2 + 7) - (4x^2 - 3x - 1)
=2x (4x^2 - 3x - 1) - 3x^2 (4x^2 - 3x - 1) + 7(4x^2 - 3x - 1)
=8x^3 - 6x^2 - 2x -12x^4 + 9x^3 + 3x^2 + 28x^2 - 21x -7
= - 12x^4 + 17x^3 + 25x^2 - 7

"化簡下列各數式
(3x+2)+(2x-3)+(-x+5)
(7x-2y)-(4x+5y)
(2x-3x^2+4+7x^3)-(4x^2+3x+2x^2-6) "

(3x + 2) + (2x - 3) + ( - x + 5)
=3x + 2 + 2x - 3 - x + 5
=4x + 4

(7x - 2y) - (4x + 5y)
=7x - 2y - 4x - 5y
=3x - 7y

(2x - 3x^2 + 4 + 7x^3) - (4x^2 + 3x + 2x^2 - 6)
=2x - 3x^2 + 4 + 7x^3 - 4x^2 - 3x - 2x^2 + 6
=7x^3 - 9x^2 -x +10

"展開
(3x-2y)(2x+3y)
(3x-1)(2x^2+x-1) "

(3x - 2y) (2x + 3y)
=2x (3x - 2y) + 3y (3x - 2y)
=6x^2 - 4xy + 9xy - 6y^2
=6x^2 + 5xy - 6y^2

(3x - 1) (2x^2 + x - 1)
=3x (2x^2 + x - 1) - 1 (2x^2 + x - 1)
=6x^3 + 3x^2 - 3x - 2x^2 - x + 1
=6x^3 + x^2 - 4x + 1

"化簡
-3x^2(2-5)+4x(3x^2+1) "

- 3x^2 (2 - 5) + 4x (3x^2 + 1)
= - 6x^2 + 15x^2 + 12x^3 + 4x
= 12x^3 + 9x^2 + 4x

"展開
(x+y)(x^2-xy+y^2)
(x-y)(x^2+xy+y^2)
(x-y)(x^4+x^3y+x^2y^2+xy^3+y^4) "

(x + y) (x^2 - xy + y^2)
= x (x^2 - xy + y^2) + y (x^2 - xy + y^2)
= x^3 - yx^2 + xy^2 + yx^2 - xy^2 + y^3
=x^3 + y^3

(x - y) (x^2 + xy + y^2)
= x (x^2 + xy + y^2) - y (x^2 + xy + y^2)
= x^3 + yx^2 + xy^2 - yx^2 - xy^2 - y^3
=x^3 - y^3

"己知一個多項式乘以x-2,所得的乘積包含-3x^2這個項,求該多項式. "
Ans.= 你條式資料唔夠，只係知條式入面有" - 3x "

"解下列各方程
6a-5=4a+3
3k-5=8k-20
2x+3+(3x-2)=6
2x+3-(3x-2)=6
3(x-1)-4=2-(x+1)
0.2x-3=-0.3x+1
4分y-5分y=10分1
4分1-2分y=4分y-8分1
2[3x9(x-2)]=3[2x(x-1)}+12 "

6a - 5 = 4a + 3
6a - 4a = 3+5
2a=8
a=4

3k - 5 = 8k - 20
3k - 8k = - 20 + 5
- 5k = - 15
k=3

2x + 3 + (3x - 2) = 6
2x + 3 + 3x - 2 = 6
5x + 1 = 6
5x = 5
x=1

2x + 3 - (3x - 2) = 6
2x + 3 - 3x + 2 = 6
- x + 5 = 6
- x = 1
x= - 1

3 (x - 1) - 4 = 2 - (x + 1)
3x - 3 - 4 = 2 - x - 1
3x + x = 2 - 1 + 3 + 4
4x = 8
x=2

0.2x - 3 = - 0.3x + 1
0.2x + 0.3x = 1 + 3
0.5x = 4
x=8

y/4 - y/5 = 1/10
5y - 4y = 2
y=2

1/4 - y/2 = y/4 - 1/8
2 - 4 = 2y - 1
2 - 4 + 1 = 2y
- 1 = 2y
y= - 1/2 or - 0.5

2 [3 x 9 (x - 2) ] = 3 [2x (x - 1) ] + 12
2 [27x - 54] = 3 [2x^2 - 2x] + 12
54x - 108 = 6x^2 - 6x +12
54x - 6x^2 + 6x = 12 + 108
60x - 6x^2 = 120
10x - x^2 = 20
x (10 - x) = 20
______20
x = --------------
_____10 - x

1)
a+2>3
a>3-2
a>1
2)
3x-4<5
3x<5+4
3x<9
x<3
-8(x-2)=4-7x
-8x+16=4-7x
-8x+7x=-16+4
-x=-12
x=12
-3(x+3)/2(x-4)=-3
(-3x-9)/(2x-8)=-3
-3x-9=-3(2x-8)
-3x-9=-6x+24
-3x+6x=24+9
3x=33
x=11
-3+2x-5x^2
=-5x^2+2x-3
=5x^2-2x+3
3x^3y-2xy^3+4xx^2-5
=3x^3y-2xy^3+4x^2-5
(2x-3)(x=2y)
(2x-3)(2y=2y)
不明
(2x-3x^2+4+7x^3)-(4x^2+3x+2x^2-6)
=(7x^3-3x^2+2x+4)-(6x^2+3x-6)
=7x^3-3x^2+2x+4-6x^2-3x+6
=7x^3-9x^2-x+10
(3x+2)+(2x-3)+(-x+5)
=3x+2+2x-3-x+5
=4x+4
(7x-2y)-(4x+5y)
=7x-2y-4x-5y
=3x-7y

1.a+2>3
a>3-2

2.3x-4<5
3x<9
x<3

解下列各方程
-8(x-2)=4-7x
-8x+16=4-7x
12=15x
x=4/5

-3(x+3)分2(x-4)=-3
-3x-9/2x-8 = -3
-2 =2x-8
x =3

按x的降冪排列下列各多項式
-3+2x-5x^2
=-5x^2+2x-3

3x^3y-2xy^3+4xx^2-5
=3x^3y-2xy^3+4x^3-5

展開
(x+y)(x^2-xy+y^2)
=x^3+y^3

(x-y)(x^2+xy+y^2)
=x^3-y^3

1.a+2>3
a>3-2

2.3x-4<5
3x<9
x<3

解下列各方程
-8(x-2)=4-7x
-8x+16=4-7x
12=15x
x=4/5

-3(x+3)分2(x-4)=-3
-3x-9/2x-8 = -3
-2 =2x-8
x =3

你一次問太多,時間有限解唔曬,解左d喇~