Answer:
-9
Step-by-step explanation:
Khan Academy huh? Well, the answer's -9.
-7 = -9 + 2
Hope that helps!
35
since m and n are the midpoints of ab and ac resistively
then ,bc=2mn=16
since m and l are the midpoints of ba and bc respectively
then, ac =2mn =10
then,nc =1/2 × 10 =5
similary, mb=6
then ,perimeter=nc+mb+mn+bc=5+6+8+16=35
a geometric sequence is a bunch of numbers where you can get from a number to the next number by multiplying the previous number by a certain number
might be confusing so here's an example
1,2,4,8,16
each term is multiplied by 2 to get next term, that number that each term is multiplied by is called the common ratio
formula for geometric sequence is

where
is nth term
is first term
r is teh common ratio
n=which term
in our example
1,3, 9, 27, 81
each term is being multiplied by 3 so it is a geometric sequence and thus r=3
also first term is 1 so 
so the formula is
or in function notation 