The middle section is n(n+1)
The top row is n+2
The bottom row is 2n+1
So the rule for the total number of tiles will be the sum of the above rules...
s(n)=n(n+1)+n+2+2n+1
s(n)=n^2+n+n+2+2n+1
s(n)=n^2+4n+3
Answer:

Step-by-step explanation:
An arithmetic sequence that is described by the explicit formula ...

can also be described by the recursive formula ...

Matching parts of the formulas, we see that a1 = 4, d = -7. Putting these values into the explicit formula gives ...

Answer:
1. C 2.D 3.D 4.A
Step-by-step explanation:
The first one would be C because the slope is -1, which can also be -x and the y-intercept is 0, meaning you don't need to add or subtract anything.
The second one is D because the slope is -3, meaning it's -3x, and the y-intercept is positive, meaning you add 5.
The third one is D because the slope is 5/4, which is 5/4x and the y-intercept is positive 3, meaning you add 3.
And the fourth one is A because there is no slope, so y would just equal 3.
Answer:
87.6
Step-by-step explanation:
The correct answer is -1.
In order to solve this, we need to split into the positive and negative version of the answers. Let's start with the positive version.
2 - x < 4
-x < 2
x > -2 ----> NOTE: When we divide by -1, we have to change the direction of the sign.
Now we'll do the negative version.
2 - x > -4
-x > -6
x < 6
So we know the number must be greater than -2, but less than 6. The only number on this list that fits that is -1.