$79.75*0.2= 15.95
$79.75-15.95= $63.80
63.80+15.95= $79.75
Answer= $15.95
I think that it's B, y = -x - 7 because first you'd subtract y to get it on the other side then add x and then you'd need to make the y positive so you would divide x + 7 by -1 and that would make it y = -x - 7.
To check for continuity at the edges of each piece, you need to consider the limit as approaches the edges. For example,
has two pieces, and , both of which are continuous by themselves on the provided intervals. In order for to be continuous everywhere, we need to have
By definition of , we have , and the limits are
The limits match, so is continuous.
For the others: Each of the individual pieces of are continuous functions on their domains, so you just need to check the value of each piece at the edge of each subinterval.