Question

(5+y)(5-y)-y(7-y) , при x= -

Answer 1

Ответ:

28

Пошаговое объяснение:

(5+y)(5-y)-y(7-y) = 25 - y² - 7y + y² = 25 - 7y

при x = -3/7

25 - 7y = 25 - 7*(-3/7) = 25 + 3 = 28

Answer 2

It seems like there is a small inconsistency in your question. You mentioned "x=" but didn't include any value for "x". However, in the expression you provided, there is a variable "y" instead of "x." Assuming you want to evaluate the expression when y = -:

The given expression is: (5 + y)(5 - y) - y(7 - y)

Now, let's substitute y with - in the expression:

(5 + (-))(5 - (-)) - (-)(7 - (-)) (5 - 5) - (-)(7 + ) 0 - ( - ) 0 + 0

So, when y = -, the value of the expression (5 + y)(5 - y) - y(7 - y) is 0.