數學求教: 3x+3-3x=3 求x

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Let the smallest number be x , then the other two numbers are (x+1) and (x+2) .

x + (x+1) + (x+2) - 3x = 3
3x + 3 - 3x = 3
3 = 3

Because 3 ≡ 3 , so x can be any number , for example we take x = 19 , then the sum of three consecutive numbers = 19 + 20 + 21 = 60 , three times the smallest number = 3(19) = 57 , the sum of three consecutive numbers minus three times the smallest number = 60 - 57 = 3 , correct .

Answer : x can be any number .

其實 x 可以任何數，因為係咪都會約左...

e.g.
sub x=1
3(1)+3-3(1)=3
3-3+3=3
3=3

sub x=2
3(2)+3-3(2)=3
6+3-6=3
6-6+3=3
3=3

.
.
.

sub x=999
3(999)+3-3(999)=3
2997+3-2997=3
2997-2997+3=3
3=3

Let x be 0,

Change 3x +3 -3x =3

to 3×0 +3 -3×0 =3

頭尾兩個3×0因為係正同負所以可以刪去，咁就會得番：

3=3

所以x=0

3x + 3 = 3x + 3
Hence there are infinite many solutions for x is real.