9x-7=-7
9x=o
x=0
so the answer....is 0
Bisector is simply a straight that divides the line (through which it's passing) into two equal halves. Or simply, it passes through the midpoint of any line. It may make any angle with the line through which it passes.
Perpendicular Bisector is also the same but the only difference is that it makes an angle of 90° with the line through which it passes or cuts.
Mr. Mole's burrow was at an altitude of 6 meters below the ground.
Step-by-step explanation:
Step 1:
We need to determine the distance that Mr. Mole covers in a single minute.
To do that we divide the difference in values of altitude by the difference in the time periods.
For the first case, Mr. Mole had traveled -18 meters in 5 minutes.
We also have, he traveled -25.2 meters in 8 minutes.
Step 2:
The distance he covered in 1 minute 

So with every minute, Mr. Mole digs down an additional 2.4 meters below the surface.
To determine where Mr. Mole's burrow is we subtract the distance traveled in 5 minutes from -18.
The altitude of Mr. Mole's burrow 
So Mr. Mole's burrow was at an altitude of 6 meters below the ground i.e. -6 meters.
A translation of Figure 1 results in Figure 2.
Answer: Option c: translation