The mean is 27
How you do this is you add all the numbers together even the ones that are duplicated like in this case 31. Now add em all up which equals 135. Now you take the number that they equal up to and divide by how many numbers are in the set of data in this case it is 5. After dividing you get 27.
I hope this helps!
Answer:
81(x + 2y)(x - 2y)
Step-by-step explanation:

The two triangles are similar and equal therefore; It means the corresponding sides are equal and the corresponding angles are equal. Hence;
ZX=EF, thus,ZX = 1.3 in.
EG = XY, thus, EG = 3.0 in.
m∠ X = m∠E, thus m ∠X = 48°
m∠ G = m∠Y, and angles in a triangle add up to 180 thus;
m ∠ G=180- (107 +48) = 25°
The equation would just be x=8 since the x of both points is 8.
9x40= 360
9x30= 270 so the common factor is 9 I have no idea about the exponent stuff