If you would like to solve the system of linear equations, you can do this using the following steps:
2x - y = -1 ... y = 2x + 1
2x + y = -7 ... y = -7 - 2x
The correct result would be: y = 2x + 1, <span>2x + y = -7.</span>
It seems that you have missed the necessary options for us to answer this question, but anyway, here is the answer. Based on the given scenario above about what Annabelle did, the kind of statistical investigation that she performed was a SURVEY. Hope this helps.
Answer: Option 'A' is correct.
Step-by-step explanation:
Since we have given that
Rational numbers are those numbers which can be written as p/q form or it must be non terminating but recurring number.
-13 can be written as p/q form as 
is a rational number because of its form.
81 can be written in p/q form as 
But √2 is non terminating and non recurring number.
Hence, √2 is not a rational number.
Therefore, Option 'A' is correct.