If you're using a computer, you can take a picture on a camera, copy the picture to your computer to upload to Brainly.
If you're using a phone, you can easily upload pictures in the brainly App when you ask a question! just hit the camera button on the bottom left.
In a file extension, it tells what type of file it is and tells what compiler to run the code.
2.5 is a float.
Float stands for floating point. Floating point types are numbers with decimal places. I hope this helps!