Answer:

Step-by-step explanation:

Multiplying positive integer and negative integer gives a negative integer i.e ( + ) × ( - ) = ( - )

The negative and positive integers are always subtracted but posses the sign of the bigger integer

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Answer:
No
Step-by-step explanation:
Say n was equal to 2
7(2) + 6 =20
13(2) = 26
Answer:
The puzzle is first add the current two numbers and then add their sum to result obtained in previous step.
Step-by-step explanation:
1 + 4 = 5
2 + 5 = 12
12 is obtained by adding 2 + 5 = 7 and adding the result obtained in previous result which is 5 to 7
⇒ 7 + 5 = 12
Now, 3 + 6 = 21
21 is obtained by first adding 3 + 6 = 9 and the previous result obtained is 12
So adding 12 to 9 ⇒ 12 + 9 = 21
Hence, The puzzle is first add the current two numbers and then add their sum to result obtained in previous step.