if /r/=4, then the value of /-5r/ is
20.
To solve this problem, we need to first simplify the expression /-5r/ using the given value of /r/ = 4.
/-5r/ = /-5(4)/
/-5r/ = /-20/
Since absolute value is always positive, the absolute value of -20 is simply 20. Therefore, /-5r/ is equal to 20 when /r/ = 4.