I want to ask Maths

2007-08-14 2:05 am
I want to ask Maths
Simplify the following algebraic expressions.

(a) 3x+x-2x

(b) 5m-5-2(2m +1)

(c) (2m+5/2)-(m-1/4)

(d) 6x(2a+7/3)+4x(3a-5/2)

(e) 3r+4s-2r+7s

(d)4x (2次)-2x+7-2x+3x(2次)+5x-2

(其實我唔系好明,唔該解一解,thx)

回答 (3)

2007-08-14 9:05 pm
✔ 最佳答案
你係唔係唔明計數字與未知數&未知數與未知數之間既運算呢?其實未知數係點樣結合,simplify? x+x=2x , x+2+3x+6+5x^2+7y=4x+8+5x^2+7y 從以上加減既例子,未知數係要完全相同先可以結合(完全相同即例如大家都係x,而次方都係2次,即x^2, 3=3x^0,與x^2不相同,x與y更加不相同,所以他們不可以結合)

但乘除既計法又唔同,會涉及到子數問題(一定),先向你介紹下一部分 x^0=1, x=X^1, (x^n)(x^m)=x^(m+n), (x^n)/(x^m)=x^(n-m)

e.g.數字=數字(未知數^0) xy=(x^1)(y^1), (x^3)x=x^(3+1)=x^4,
3x=3(x^0)(x^1)=3[x^(0+1)]=3x, 5(x^3)/6(x^4)=(5/6)[x^(3-4)]=5/6x...


答案樓上都有,有d咩唔明e-mail比我
[email protected]
2007-08-14 2:22 am
第一我不明白你是不明甚麼,如果可以,請說出.
(a) 3x+x-2x
=4x-2x
=2x

(b) 5m-5-2(2m +1)
=5m-5-(4m+2)
=5m-5-4m-2
=m-7

(c) (2m+5/2)-(m-1/4)
=2m+5/2-m+1/4
=m+10/4+1/4
=m+11/4

(d) 6x(2a+7/3)+4x(3a-5/2)
=12a+7/3+12a-5/2
=24a+14/6+15/6
=24a+29/6

(e) 3r+4s-2r+7s
=3r-2r+4s+7s
=r+11s

(f)4x (2次)-2x+7-2x+3x(2次)+5x-2
=4x (2次)+3x(2次)-2x-2x+5x+7-2
=7x(2次)+x+5
2007-08-14 2:12 am
a)2x
b) 5m-5-4m-2=m-7
c)2m+5/2-m+1/4=m+11/4
d)12xa+14x+3ax-10x=15ax+4x=x(15a+4)
e)r+11s
f)7x(2次)+4x+5

2007-08-13 18:13:59 補充:
b)乘2入去再計c)拆括號d)expand 開哂, 再減, 然後抽x


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