Answer:
-27
Step-by-step explanation:
9(4x – 15)
Substitute 3 for x
9((4)(3) - 15)
Multiply (4)(3) = 12
9 ( 12 - 15 )
Subtract 12 - 15 = -3
9(-3)
Multiply 9(-3) = -27
There are 20 gallons of 20% butterbeer solution.
Assume there are x gallons of 80% solution.
So total amount of the solution will be (x+20) gallons
The final solution is 50%.
So, we can set up the equation as:

.
Thus, there will be 20 gallons of 80% butterbeer solution that is needed to be mixed with 20 gallons of 20% butterbeer solution.
2x + x = 180
This is because 2x is on one side while x is on the other, if those two angles add up they must add up to 180 because the two angles form a 180 degree angle or just a straight line
2x + x = 180
3x = 180
x = 60
The answer to 0.15 x 22 is 3.3
If you look after the decimal point, you only see one digit (.3)
Therefore the answer is 1