Answer:
The value of the expression, when r = 4 is "-4".
Explanation:
Given the expression "- 3 r + 8", when we evaluate it at r = 4, we simply replace "r" with the given value "4" in the algebraic expression they give us, and perform the indicated operations among numbers:
-3 (4) + 8 = -12 + 8 = -4
Therefore, the requested value is: "-4".