I assume #3 is 19 because the slope of the line is still the same.
Hope this is right and it helps! I'm not very sure though.
Hope This Helps. Have a good day.
Answer:

Step-by-step explanation:
A circle centered at (0,0) with radius r is 
Since your circle has diameter of 12, then its radius is 6. Then 
So a possible answer is: 
If you want to move the location of the center, but keep it on the x-axis, then add or subtract a number to the x, such as this:

The center of this circle would be (-4, 0) which is still on the x-axis.
Answer:
yes
Step-by-step explanation:
9 can be represented as 9/1, which is the reciprocal of 1/9.
Answer: 50 texts
Step-by-step explanation: 20.8 - 5.80 = 15
15 ÷ .30 = 50