the length of a book is 2.75 times greater than the width. Write and simplify an algebraic expression for the perimeter of the box in terms of the width w.
No, this is not simplified fully. The full answer would be −7dk+14d−21k−7, not 14d - 9 - 21k - 7dk + 2. So, it is not equivalent. Excercise 4: 7dk (2 - 3 - 1) - 7
Just multiply 7dk into (2) (-3) and (-1) you'd get: −14dk+−7 after simplifying it fully.