The first step for solving this expression is to remove the first set of parenthesis.
9r - 5 - (-4 + 9)
In order to find the sum inside the parenthesis we must keep the sign of the number with the larger absolute value and subtract the smaller absolute value from the larger. This will look like the following:
+ (9 - 4)
Now subtract the numbers and add it back into the expression.
9r - 5 - 5
Now we will calculate the difference between -5 - 5 and add it back into the expression.
9r - 10
Since we cannot simplify this any further,, 9r - 10 is going to be the correct answer to your question.
Let me know if you have any further questions.
:)
