A general equation to use for this situation is y = mx + b.
For this question, we can assume that y is total cost, m is cost per balloon, x is the amount of balloons, and b as the service fee; so we can set the equation up:
y = (4.50)x + 12
And we can further plug in the total cost to find the number of balloons purchased for the party:
79.50 = (4.50)x + 12
Now we can solve for x (number of balloons):
67.50 = (4.50)x
x = 15
The total number of balloons purchased for the party is 15.
Answer: Just apply the formula
Step-by-step explanation:
The equation for volume of a cone is:

The radius is the line that creates a 90 degree angle with the height
The height goes from the base to the tip of the cone.
I recommend leaving Pi as it is and plugging the rest of the numbers first.
Then at the end multiply by 3.14 and round at the end.
This way, it is easier to avoid calculation errors.
The answer is the last option, hope this helps lol
Answer: 1/10 or 0.1
Step-by-step explanation:
-(-7 - 4x) = -2(3x - 4)
7 + 4x = -6x + 8
* subtract 7 from both sides
4x = -6x + 1
* Add 6x to both sides
10 x = 1
* Divide both sides by 10
x = 1/10 or 0.10