math 快快快!!! 幫幫手

1)
2E1 <= 16進制吧
= 2*16^2 + 14*16^1 + 1*16^0
= 2*16^2 + 14*16 + 1*1
= 2*256 + 224 + 1
= 512 + 224 +1
= 737

110110 <= 2進制吧
= 1*2^5 + 1*2^4 + 0*2^3 + 1*2^2 + 1*2^1 + 0*2^0
= 1*32 + 1*16 + 1*4 + 1*2
= 54

37 <= 10進制吧
(最好用直式 cannot show you here, sor)

= 32+ 4 + 1
= 1*2^5 + 1*2^2 + 1*2^0
= 100101

2)

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

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

c) (-a^2+3a-4)-(a^2-a+1)
= -a^2 + 3a - 4 - a^2 +a -1
= -a^2 - a^2 +3a + a -4 -1
= -2a^2 + 4a -5

2008-08-27 19:53:31 補充：
recommend you an online scientific calculator:
http://www.bithkfor.com/cc.htm

2a. (3x+2)+(2x-3)+(x+5)
= 3x+2+2x-3+x+5
= 6x+4 / 2(3x+2)

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

2c. (-a^2+3a-4)-(a^2-a+1)
= -a^2+3a-4-a^2+a-1
= -2a^2+4a-5

(1)指數和數系
把2E1轉換為十進數。737
把110110轉換為十進數。54
把37轉換為二進數。100101
(2)化簡下列各數式
(a)(3x+2)+(2x-3)+(x-+5)
=6x-6

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

(c)(-a2+3a-4)-(a2-a+1)
=-2a2+4a-5