1)7x - 40 = 4x + 14
7x- 4x = 14 + 40
3x = 54
x = 18

2)16x + 72 = 12x + 108
4x = 36
x = 9

3)7(3+k)=33+5k
21+7k=33+5k
7k-5k=33-21
2k=12
k=6

Ответы и объяснения

2014-02-13T17:20:38+04:00
7x - 40 = 4x + 14
7x- 4x = 14 + 40
3x = 54
x = 18

16x + 72 = 12x + 108
4x = 36
x = 9

 7(3+k)=33+5k
21+7k=33+5k
7k-5k=33-21
2k=12
k=6
2014-02-13T17:24:33+04:00
1) 7х-40=4х+14                       
 7х-4х=40+14
 3х=54
 х=54/3
 х=18
2)16х+72=12х+108
16х-12х=-72+108
4х=36
х=36/4
х=9