I might be wrong but I think the answer would be -x+2x+6 as a simplified version because if you use the equation (x+4•x+3)-3x(x+1)=a (or any letter you choose), you will get 3x+x^2+12+4x-3x-3x^2=y. Then, you can combine like terms:
4x-2x+12=a
First we need to know how much each pen costs. So we take 11.77 and divide it by 11. That gives us 1.07 per pen. So answer choice A has 4 pens for 4.44, so we need to multiply 1.07 x 4. That gives you 4.28, so we know that isn't the correct answer. For option B, we need to multiply 1.07 x 5. That is 5.35, so that also can't be the answer. For C, we need to do 1.07 x 6, and that gives us 6.42. So we know the correct answer is option C.
When you have a negative exponent, you move it to the other side of the fraction to make the exponent positive.
For example:
or 
or y²
So:

Your answer is B
The answer would be 3n^2 + 2.
This can be found/proven by replacing "n" with term number (1,2,3,4...), then solving to get the final number. For example 3 * 1^2 + 2. You would first do 1^2, which is 1. Next, you would multiply 1 by 3, to get 3. Finally, you'd and the 2 to get 5. 5 is the 1st term, and you can use this same equation to get the rest of the terms you need.
I hope this helps!
Answer: An expression for the height is: H = (3/64)V
To start with, we will assume that it is a square pyramid, meaning all the sides of the base are 8 feet wide.
Now, we need the formula for the volume of a square pyramid.
V = BH/3
We know the area of the base, it is 8 x 8 = 64, so we can input that.
V = 64H/3 We can multiply by 3/64 to find an expression for the height of the fort.
(3/64)V = H