幾條數學問題

[a二次=a^2]
1把2E1(16)轉換為十進數:
2x16^2+14x16+1x1=737(10)

2把110110(2)轉換為十進數:
1x2^5+1x2^4+0x2^3+1x2^2+1x2+0x1=54(10)

3把37(10)轉換為二進數
2!___37___
2 !__18___.........1
2!__9___..........0
2!_4____.........1
2!_2___..........0
1................0
37(10)=100101(2)

4把444(10)轉換為十六進數:
16!___444__
16!_27___........C
1..............B
444(10)=1BC(16)

1(a+b+1)(a+b-1)=[(a+b)+1][(a+b)-1]
=(a+b)^2-1^2
=a^2+2ab+b^2-1

2(a+b+c+d)(a+b-c-d)
=[(a+b)+(c+d)][(a+b)-(c+d)]
=(a+b)^2-(c+d)^2
=(a^2+2ab+b^2)-(c^2+2cd+d^2)
=a^2+2ab+b^2-c^2-2cd-d^2

( x二次+x+1)(x二次-x+1)
=[(x^2+1)+x][(x^2+1)-x}
=(x^2+1)^2-x^2
=x^4+2x^2+1-X^2
=x^4+x^2+1

a)500的40%=500x40%=200
b)x的x%=x*x%=x^2%

一個產品的標價是$50，其中成本是$40，而售價是$36
(a)求交易的盈虧率
(36-40)/40=-4/40=-10%

b)這個產品的標價較成本高出百分幾?
(50-40)/40=10/40=25%

2E1 (16)=2x16^3+14x16^2+1x16=8192+3584+16=11792 (10)
110110 (2)=1x2^6+1x2^5+0x2^4+1x2^3+1x2^2+0x2=64+32+8+4=108 (10)
37 (10)=100101 (2)
444 (10)=1BC (16)

2007-08-20 20:58:54 補充：
(a b 1)(a b-1)=(a b)^2-1=a^2 2ab b^2-1(a b c d)(a b-c-d)=(a b)^2-(c d)^2=a^2 2ab b^2 c^2 2cd d^2(x^2 x 1)(x^2-x 1)=x^4-x^3 x^2 x^3-x^2 x x^2-x 1=x^4 x^2 1500x40%=200x的x%=(x^2)%(36-40)/40x100%=-10%(50-40)/40x100%=25%