The evaluated value of the expression is 38.
Using the parameters given for our Calculation; 
Inputting the values of b and c into the expression 
c - 5b 
3 - 5(-7)
3 - (-35)
3 + 35 
= 38
Hence, the expression is 38
Complete question 
evaluate the express when b=-7 and c=3 c -5b