Usually the question will be in coordinate notation (a graph). If they want you to reflect across the x-axis here are the steps you need:
1. what are the coordinates of the line? Example: (2,3), (5,2)
2. (x,y) becomes (x, -y) so the sample points would change to (2, -3), (5, -2)
3. There you have it! If you need to graph your points go ahead. You should now have the line reflected across the x-axis
If they want it reflected across the y-axis use the same steps, but for step 2 instead the rule is (x,y) becomes (-x,y)
Another common one is reflect it over the line y=x. Again, same steps, but for step 2 the rule is (x,y) becomes (y,x)
If you want to see this visually here is a good source:
Reflection means we take the mirror image of a shape, where the mirror would be, we call it the line of symmetry. it stays the same but changes in direction. You may find questions that will ask you for the reflection of a line.
You can use tracing paper to help reflect your shape.
Every point on a rotated shape is at the same distance from the point of rotation. It stays the same size, but changes in direction.
Rotation about a point
Imagine a shape that has been cut out from some paper, and placed on the graph. If you want to rotate it about a spot, you can stick a pin where the 'spot' is, and as you spin the shape, that is rotation about a spot.
Cutting out the shape is a useful way to practice rotation, but you will not have scissors in your exam!
Remember, every point on the rotated shape must be the same distance from the spot as the original shape.