Series Completion

The solution is :
7 * 1 + 2 = 9 
9 * 2 + 3 = 21 
21 * 3 + 4 = 67
67 * 4 + 5 = 273≠  275
273 * 5 + 6 = 1371
1371 * 6 + 7 = 8233
Therefore, wrong no. is 275

The solution is:
3 * 2 + 2 = 8 
8 * 2 + 2 = 18
18 * 2 + 2 = 38
38 * 2 + 2 = 78 ≠80
78 * 2 + 2 = 158
158 * 2 + 2 = 318
Therefore, wrong no. is 80

Therefore, it must be 42+14 = 56 i.e. 127+56 = 183
56+ 15 = 71  i.e. 183+ 71 = 254
Hence, wrong no. is 185

The solution is :
3 * 2 = 6 
6 * 2.5 = 15
15 * 3 = 45
45 * 3.5 = 157.5 ≠  157
157.5 * 4 = 630
630 * 4.5 = 2835
Therefore, wrong no. is 157