x-y=7

x - y = 7

(x - y)² - 5x+5y

I'm guessing that you're trying to figure out what the second expression equals when you use the information from the first equation.

First just look at this second expression.

(x - y)² - 5x+5y

 

Factor out a -5 from the last two terms.

(x - y)² - 5(x - y)

 

Now substitute 7 in for every (x - y).

7² - 5(7)

 

49 - 35 = 14