Given r = 3 and i = 8, substitute these values into the expression 5r - i + 4:
5 * 3 - 8 + 4
Now, perform the multiplication and addition/subtraction:
15 - 8 + 4
Finally, perform the subtraction and addition:
7 + 4
This gives us:
11
So, when r = 3 and i = 8, the value of the expression 5r - i + 4 is 11.
