0= -3x+9
-9=-3x
3=x
Final answer: x=3
There is only one zero because it is linear, and can therefore only cross the x axis once.
Answer:

Step-by-step explanation:
Given:
Width of average grain of salt is, 
Width of Rhinovirus is, 
Now, expressing each width in scientific notation form, we get:

Now, in order to get how many times 'W' is wider than 'w', we divide the two widths. This gives,

Therefore, the grain of salt is
wider than Rhinovirus.
In order to solve this, you have to plug in all of the costs of the gifts and add them, which in all equals $36. since jim only has 1/4 of the money he needs to buy the gifts, you need to divide 36 by 4. this gives you 9, so now you know he has 9 dollars.
and to find out how much more money he needs, you can subtract 9 from 36 which represents a fourth of the required money. the answer is 27, that's how much jim needs in order to buy his gifts.
Answer:
Let x be the number of silver medals.
As there were two more gold medals than silver ones, gold medals are x+2
We also know that the number of bronze medals was 4 less than the sum of gold and silver, so if there are x + 2 of gold and x of silver, there are x+x+2-4 of bronze.
Now, we can do an equation, as we know there were a total of 28 medals:
x + x + 2 + x + x + 2 - 4 = 28
And we isolate x:
4x = 28
x = 28/4 = 7
There were 7 silver medals, so there were 9 gold ones (7-2) and 12 of bronze (9+7-4).
5 would be the dependent variable because the number 5 depends on how many greeting cards are bought.