Answer:
yep thats correct
Step-by-step explanation:
and 
use the second expression to calculate the left-hand side of the first equation:

Add 10 to both sides if this equation to get

and divide both sides by 2

this proves that x = 17, give the two initial equations
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.
What following are you choosing from
Answer:
90
Step-by-step explanation: