1. The problem statement, all variables and given/known data 3. The attempt at a solution My book is not explaining very well the steps at solving these problems. There is a step that I'm missing step 1. find 1/(b-a) easy step 2. find the antiderivative of 4 - x, easy, x^2/2 step 3. plug in what the result of the antiderivative is for b and a, subtract b from a step 4. this is the step I'm missing. the books shows that I'm supposed to multiply 4 by b - a. why? what is this? I need to know what mathematical terminology this is so that i can do these problems in the future step 5. subtract step 4 from step 3. why? what mathematical terminology is this. step 6. multiply step 1 by step 5, I understand that. I'm not yet able to read the notation and the book is not helping.