Answer:
There are 111 blue bags
Step-by-step explanation:
Let
x ----> the number of black bags
y ---> the number of blue bags
we know that

isolate the variable y
-----> equation A
----> equation B
substitute equation B in equation A
therefore
There are 111 blue bags
slope =(y2-y1)/(x2-x1)
m=(-1-5)/(1--1)
m=-6/2
m=-3
y-y1=m(x-x1) point slope form
y-5 = -3 (x--1)
y-5 = -3 (x+1)
distribute
y-5 = -3x -3
add 5 to each side
y = -3x+2
Choice D