Question 4837
simplifying means to Use the order of operations:
Parentheses
Exponents
Multiplication/Division
Addition/Subtraction

6r+5r-8p+7(2r-4r)

Perform the operation in the parentheses:
6r+5r-8p+7(-2r)
Clear the parentheses using multiplication:
6r+5r-8p+-14r
Perform addition/subtraction from left to right
11r-8p-14r
Rewrite the equation as:
11r-14r-8p
Perform addition/subtraction again:
-3r-8p

Nothing else can be performed so the answer is 
-3r-8p