Answer:
6
Step-by-step explanation:
-3 -1 +2 +8 = -4+10 = 6
Answer:
3.81 = 3 81/100
Step-by-step explanation:
This can’t be simplified so it stays as 3 

P.S. Hello from Russia :^)
Answer: Length = 15, Width = 12
Step-by-step explanation:
L = length
W = width
L = W+ 3
perimeter = 2L + 2W
54 = 2(W+3) + 2W
54 = 2W + 6 + 2W
54 = 4W + 6
54 - 6 = 4W
48 = 4W
W = 
W = 12
now to find the length, plug the width into the equation L = W + 3
length:
L = W+3
L=12 +3
L = 15
B: (0, a)
C should have the same y value as B
D: (a,0)
C should have the same x value as D
So point C is (a,a)
Since point A is on the origin, its point is (0,0)
You use the slope formula and plug in point A and C:



m = 1
So the value that belongs in the green box is 1