I'm pretty sure that it is C. 12
Answer:
The most frequently employed tools are traditional, which include physical ... These three tools can be used independently or conjointly, depending on the type of ... Learning tools can represent mathematical ideas in multiple ways, providing ... nature of concepts, such as numbers, thereby making them real and tangible,...
Step-by-step explanation:
Let's call that number x, twice the number will be 2x, sum of it and 5 is, 2x+5. So if this expression is at most 15, it means, it can be only less than 15 and equal to 15. Let's show this as an inequality.

Let's solve.

![x\quad \in \quad \left[ -\infty ,5 \right]](https://tex.z-dn.net/?f=x%5Cquad%20%5Cin%20%5Cquad%20%5Cleft%5B%20-%5Cinfty%20%2C5%20%5Cright%5D%20)
If the number is a natural number. The values it can take is,
Answer:
7f
r = ----------- - 4
z
Step-by-step explanation:
I will assume that you meant:
7f
z = ------------
r + 4
Solve for r. Start by interchanging z and (r + 4):
7f
r + 4 = -----------
z
Now subtract 4 from both sides. This isolates r:
7f
r = ----------- - 4
z
Answer:
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