She is not correct.
The GCF for 2x^2 + 4xy + 8xy^4
is 2x
The first term does not have a 'y' in it so you cannot have a 'y' in the GCF.
The second and third terms both only have 1 'x', so you can only take out 1 'x', not 2.
The highest constant that all three terms have in common is a 2.
You're expression is correct if it's asking for a number that is less than 7. But if the problem is asking for some number less than seven as in seven less some number, then it's 7-n. For example: 4 less than 7 is 7-4.
Hope this helps!
The answer is -3y-1. Whatever equation equates to that same answer would be your solution!
Answer is r = 2.5
First find the ratio of triangle like sides
11 / 4 = 2.75 ratio
Now divide 7 by ratio 2.75 = 2.5
