Substitution.
Here is an example.
Let x be equal to 3 and y equal to 3.

From this we can conclude that the values of both x and y are equal to three therefore x and y have the same value and are equal.

Here in your case we have:

Hope this helps.
r3t40
Answer:
HI! I think the answer is 4.
Answer:
37 & 67
Step-by-step explanation:
11 & 33
42 & 56
- 42 - 1, 2, 3, 6, 7, 14, 21, 42
- 56 - 1, 2, 4, 7, 8, 14, 28, 56
- Both 42 and 56 are composite numbers
- 42 & 56 is incorrect
37 & 67
- 37 - 1, 37
- 67 - 1, 67
- Both 37 and 67 are prime numbers
- 37 & 56 is correct
57 & 97
- 57 - 1, 3, 19, 57
- 97 - 1, 97
- 57 is a composite number, 97 is a prime number
- 57 & 97 is incorrect
The answer is: " 9a² + 7a " .
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Note: (3a)² + 7a = (3a)*(3a) + 7a = 9a² + 7a .
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