9.This is because it goes through the whole circle passing through the centre point. at the full width
The rest are pretty easy. I'm sure you can manage. Good luck!

Lets expand both multiplications first.

Simplify down the right side.

Add 38.25 to both sides.

Subtract 11.22x from both sides.

Divide by -21.42 on both sides. Because we're dividing by a negative, we need to change the inequality direction.

This means, out of the options available, (-2.5, ∞) is the correct answer.
<span>n >= 1125
First, make an equation to express the money raised after expenses.
55n - 15n + 10000 = m
The above expression can be read as "55 dollars per running is raised, but 15 dollars is spent per running to support them. Plus we get 10000 as a constant regardless of how many runner we have." Now convert that to an inequality for at least 55000 to be raised.
55n - 15n + 10000 >= 55000
Now solve for n
55n - 15n + 10000 >= 55000
40n + 10000 >= 55000
40n >= 45000
n >= 1125
So there needs to be at least 1125 runners in order to meet the goal of $55,000.</span>