What is the expression that shown 18+(-13)-11

The expression shown is an arithmetic expression. An arithmetic expression results in a numeric value.
The answer by the way is -6.

- 48r ^2 - 10r + 3

I use the box method for this, however, you can also use the FOIL method for this.

In the box method, draw a square and divide it into four smaller squares. On top of the first row of squares, input the first formula or ( 6r - 1 ) and on the left input the next equation to the side - don't forget whether or not the numbers are negative or not!

After that, multiply like normal - in the first box, multiply the number on top and the number on the left, etc ( If you need clarification, feel free to message me! )

Hope this helps!