Maths question...

5x-(30-x)=60
問題係咁既,

5x-30+x=60
先除左括號,
負正得負-(30)=-30
負負得正-(-x)=x

6x-30=60
簡化x,

6x-30 +30 =60 +30
各加30

6x=90
得數

(6x)/6=90/6
各除以6
x=15
得數

5x-30+x=60
6x-30=60
6x=60+30
x=90/6
x=15

5x-30+x=60
5x+x=60+30
6x=90
x=15

5x-30+x=60
6x-30=60
6x=60+30
6x=90
x=15

5x-(30-x)=60
5x-30+x=60
6x-30+30=60+30
6x=90
6x/6=90/6
x=15

5x-(30-x)=60

5x-30+x=60

6x-30=60

6x-30+30=60+30

6x = 90

x = 15

5x-(30-x)=60

5x-30+x=60

6x-30=60

6x=60+30

6x=90

x=90/6

x=15

5x-(30-x)=60
5x-30+x=60
6x-30=60
6x-30+30=60+30
6x = 90
x = 15

5x-(30-x)=60
5x - 30 + x = 60
5x + x = 60 + 30
6x = 90
x = 15

2006-10-19 22:03:35 補充：
若一題數包含有括號的話, 請留意括號外的那個符號, 是負(-)的話, 括號裹的數就要由正變負, 負變正了.5x-(30-x)=605x - 30 + x = 60>>> -30 + x 這便是例子.

5x-(30-x)=60
5x-30+x=60
6x=90
x=15