Answer:
25x^2 -1
Step-by-step explanation:
If you multiply parentheses:
(5x*5x) + (5x*-1) + (1*5x) + (1*-1)
25x^2 - 5x + 5x -1
25x^2 -1
A simpler way is to memorize this formula
(Square1 - square2)= (sqrt of square1- sqrt of square2)*(sqrt of square1 + sqrt of sqaure2)
