Answer:
b
Step-by-step explanation:
if you subtract 5x then you will get y=-10-5x
The given formula 
Solve for y means we have to make y alone
\\
Add -10 on both sides, we get

As there is multiplication sign between r and y so to solve for y, divide both side by r

The answer is 8 1/4 hours
Answer:
12m
Step-by-step explanation:
Given that the area of the square DVD case is 144 square cm
Since Area = L²
144 =L²
L = √144
L = 12m
Since the width of the DVD and its case are the same, hence the with of the DVD is also 12m