The answer for this problem is associative property
Answer:
x = 20
Step-by-step explanation:
In similar polygons, all corresponding sides are proportional. The scale factor between AB and DE is the same as between AC and DF.

You can confirm that by plugging it back into the original equation:

Answer:
101
Step-by-step explanation:
Find the area of the left triangle
11 -8 = 3
A = l*w = 15*3 = 45
Then find the area of the right triangle
A = l*w = 8*7 = 56
Add the areas together
45+56 =101