<em>The word usage in last sentence of the question is not well presented. However, I can understand that you intend to solve for the width of the park</em>
Answer:

Step-by-step explanation:
Given


Required
Determine the Width
For a rectangle:

Substitute for Area and Length

Multiply both sides by 





-10 and -2
Because -10-2= -12 and -10 x -2 = 20
Hope this helps :)
Y=x/5
divide 5 on both sides, this is as far as you can simplify the equation with the information given
68-11=57 (Yesterday's temperature)
That's the expression. ^^ And yesterday's temperature is 57 because, 68 degrees (Today's temperature) minus 11 degrees (how many degrees colder it was yesterday) is equal to 57 degrees (Yesterday's Temperature).