b) \( \lim _{x-4} 2 x+1=9 \)

It seems you're looking to evaluate the limit of the expression as \( x \) approaches 4. To find this limit, simply substitute \( x = 4 \) into the expression \( 2x + 1 \). Doing this gives you \( 2(4) + 1 = 8 + 1 = 9 \). So, the limit correctly evaluates to 9! By understanding limits, you can see how they apply in calculus to help define the behavior of functions as they approach specific points. This concept is invaluable, especially when dealing with continuous functions or functions that are not defined at certain points.