The other factor would be 9x
Answer:
D. 165
Step-by-step explanation:
if A+n=180
75+90+n=180
165+n=180
n=180-165
n=15
A+n=180
A+15=180
A=180-15
A=165 (D)
Answer:

Step-by-step explanation:
The given equality is

Take the term
to the left hand side. This means the term
will be divided by 

Now since both the numerator and denominator have negative sign the value of fraction will be positive.

Now
and 

So, the missing factor 
If you have 8 yellow balloons for every 12 blue balloons, then if you have 20 balloons in total, 8 out of 20 of those balloons will be yellow. Then you can set up this ratio.
Then, you can use either cross multiplication or multiply the numerator and denominator by the same number to help solve for x. Personally, I prefer cross multiplication.
Finally, solve for x and if you had 100 balloons, you will have 40 yellow balloons.