Which of the following is wrong?
1.a+b=b+a
2.3a=a+a+a
3.3a+b=3ab
4.a³=a‧a‧a
F.1數學問題急急急急急急急!15點
2012-01-13 3:55 am
回答 (9)
2012-01-20 12:36 am
✔ 最佳答案
s1uNanJa1 您好！我是 lop，高興能解答您的問題。(1)
L.H.S
= a + b
= a + b + (a-a)
= a + b + a - a
= (a-a) + (b+a)
= 0 + ( b + a )
= b + a
= R.H.S.
Correct
(2)
L.H.S.
= 3a
= (1+1+1)a
= 1a + 1a + 1a
= a + a + a
= R.H.S.
Correct
(3)
L.H.S.
= 3a + b
= 1(3a) + b(3a/3a)
= 1(3a) + (b/3a)(3a)
= (1+b/3a)(3a)
= (3a)(1+b/3a)
≠ (3a)(b)
= 3ab
= R.H.S.
Wrong
(4)
L.H.S.
= a³
= (a¹⁺¹⁺¹)
= (a¹)(a¹)(a¹)
= (a)(a)(a)
= a‧a‧a
= R.H.S.
Correct
Answer : (3) is wrong .
參考: Hope I Can Help You ^_^ ( From me )
2012-01-22 4:45 am
3 is wrong.
becoz 3a+b not equal to 3ab
for an example,
let a be 2 and b be 3
3a+b=3(2)+3
=6+3
=9
3ab=3(2)(3)
=18
so that 3a+b is not equal to 3ab.
becoz 3a+b not equal to 3ab
for an example,
let a be 2 and b be 3
3a+b=3(2)+3
=6+3
=9
3ab=3(2)(3)
=18
so that 3a+b is not equal to 3ab.
2012-01-18 2:31 am
3 is wrong
because only 3a x b =3ab
because only 3a x b =3ab
2012-01-13 8:08 pm
3. 3a+b=/=3ab
2012-01-13 4:16 am
Only number 3 is wrong.
2012-01-13 4:03 am
3係錯 是咁.......
收錄日期: 2021-04-13 18:29:08
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