Answer:
A. 2x, -4y, and 8
Step-by-step explanation:
If there is a minus sign in front of the 4 (-), add that to the expression. What you are just simply doing is separating the numbers up. For example:
12x - 8y + 4x
Now here, you have two of the same variables (x, y, etc). So, what you do is look at the last number that has the same variables, which is 4, and look at what the problem you will be solving, which is addition. So, very simply, you add then together!
12× + 4× = 16×
As you can see I kept the same variable. This is because, well, it is the same! Simply, just substitute in the 16× with the 8y. Now here is the tricky part, for some people. Do you see that there is a negative sign in front of the 8 (-)? Well! You have to substitute that in with the expression. No adding this or anything, just simply slide it next to the 16× because, we can not add nor subtract it with the 8y just because it has a different variable.
Your example answer would be: 16× - 8y
Hope this helps!
P.S. if you think this helped you at all, Brainliest me if ya want to. Have a great day!
81.
Add them all and then divide by the number of days (by 5)
Answer:
The correct answer B) The volumes are equal.
Step-by-step explanation:
The area of a disk of revolution at any x about the x- axis is πy² where y=2x. If we integrate this area on the given range of values of x from x=0 to x=1 , we will get the volume of revolution about the x-axis, which here equals,

which when evaluated gives 4pi/3.
Now we have to calculate the volume of revolution about the y-axis. For that we have to first see by drawing the diagram that the area of the CD like disk centered about the y-axis for any y, as we rotate the triangular area given in the question would be pi - pi*x². if we integrate this area over the range of value of y that is from y=0 to y=2 , we will obtain the volume of revolution about the y-axis, which is given by,

If we just evaluate the integral as usual we will get 4pi/3 again(In the second step i have just replaced x with y/2 as given by the equation of the line), which is the same answer we got for the volume of revolution about the x-axis. Which means that the answer B) is correct.