F.1升F.2嘅Ｍaths題(10分)

1. 設B嘅年齡係X , A 嘅年齡係X+14
X+14+2=2(X+2)
X+16=2X+4
12=X
X=12

B嘅年齡係12 A嘅年齡係12+14=26

2. 1個月後王小姐的投資值: $1000000 X 5%=$50000

化簡下列各方程
(a)(-a2+3a-4)-(a2-a+1)
=(-2a+3a-4)-(2a-a+1)
=(a-4)-(a+1)
=a-4-a-1
=-5
(b)(2a-3a2+4+7a3)-(4a2+3a+2a2-6)
=(3a+4)-(15a-6)
=3a+4-15a+6
=-12a+10
=-2(6a-5)
(c)-3a2(2a-5)+4a(3a2+1)
=-6a(2a-5)+4a(3a2+1)
=-12(a^2)+30a+24(a^2)+4a
=12(a^2)+34a
=2( 6(a^2)+17a )

展開
1.(a-y)(a4+a3y+a2y2+ay3+y4)
=(a-y) (4a+3ay+4ay+3ay+4y)
=(a-y) (4a+10ay+4y)
=4(a^2)+10(a^2)y+4ay-4ay-10a(y^2)-4(y^2)
=4(a^2)+10(a^2)y-10a(y^2)-4(y^2)
=2(a^2)(2+5y)-2(y^2)(5a+2)
2.(a+b+1)(a+b-1)(設y=a+b)--->代y入去
(y+1)(y-1)
=y^2-1^2
=y^2-1
=( (a+b)^2 )-1
=a^2 -2ab+ b^2-1
3.(a+b+c+d)(a+b-c-d)(設y=a+b&p=c+d)--->代y&p入去
(y+p)(y-p)
=y^2-p^2
=(a+b)^2 - (c+d)^2
=a^2 +2ab + b^2 - (c^2 +2cd + c^2)
=a^2+2ab+b^2-c^2-2cd-c^2
4.(y2+y+1)(y2-y+1)(設x=y2+1)--->代x入去
(x+1)(x-1)
=x^2-1^2
=x^2-1
5.(x-y)(x+2y)
=x^2+2xy-xy-2(y^2)
=x^2+xy-2(y^2)
6.(2m-5)(m-4)
=2(m^2)-8m-5m+20
=2(m^2)-13m+20
7.(3y-1)(2y2+y-1)
=(3y-1)(5y-1)
=15(y^2)-3y-5y+1
=15(y^2)-8y+1

1.2a2-3 x 2a-3=?
4a-3 x 2a-3
=4a-6a-3
=-2a-3

1.解下列各方程
(a)-x-2)=4-7x
-x-20=4-7x
-x+7x=4+20
6x=24
x=4
(b)2(x-40)分-3(x+3)=-3
2x-80-3x-9=-3
-x=86
x=-86
(c)6a-5=4a+3
6a-4a=3+5
2a=8
a=4
(d)3k-5=8k-20
3k-8k=-20+5
-5k=-15
k=3
(e)2x+3+(3x-2)=6
2x+3+3x-2=6
5x+1=6
5x=5
x=1
(f)3(x-1)-4=2-(x+1)
3x-3-4=2-x-1
3x-7=-x+1
4x=8
x=2
(g)0.2Y-3=-0.3Y+1
0.2Y+0.3Y=1+3
0.5Y=4
Y=8
(h)4分1-2分x=4分x-8分1
1/4-X/2=X/4-1/8
X=1/2=0.5
(i)2(y-2)-3(y+1)-5=3-5(y+1)
2y-4-3y-3-5=3-5y-5
4y=10
y=2.5
>>>(j)2分3(y=1)-6分5=-3分1(y-2) [在方程2方各x6)
唔明呢題講咩 可唔可以講清楚d?

自己功課自己做,5係比o黎做咩

大佬，你d a2者係咩呀a2次方就應該寫a^2啦
2a2-3 x 2a-3
係2a^(2-3)X2a^9-3)定2a^2-3X2a-3