Question

A classmate simplifies the expression in exercise 1. is the expression he wrote equivalent to the original expression? explain.

exercise 1: 14d - 9 - 21k - 7dk + 2
exercise 4: 7dk (2 - 3 - 1) - 7

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.

Answer 1

Excercise 1:

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.

p = parameter
w = width

w+2.75

p = 2w+2(w+2.75) = 4w+5.5 = 30

Answer to the last one:

w = 6.125