Question

Which expressions are differences of squares?

Select each correct answer.

t^2−1

n^2−225

k^2+81

p^2−40

Answer 1

a²-b² is diffrence of squares

first one is
t²-1², yep

2nd one
n²-15², yep

3rd one is not difffernce

4th one can be forced into p²-(2√10)², but I wouldn't say it is



first 2

Answer 2

t^2-1 and n^2-225

I don't think k^2+81 because of the "+" sign, only "-" signs are differences of squares.