Question

Plz help these r the last of my points

Answer 1

Add all the widths of the bookcases together and you get 334,

456 - 334 = 122, divide by two gets 61.

The formula would be:
w = 456 - (a + b + c) / 2

Hope this helps.

Answer 2

w=61, the equation is w=(456-a-b-c)/2,  so the work would look like 456-132-94-108=122/2=61