Answer:
25x^2-1
Explanation:
so you have to use the FOIL method which is F: First O: Outer I: Inner L: Last
So for (5X+1)(5X-1) you multiply 5x by 5x
which equals 25x^2
then you multiply 5x by -1 which is -5x
then you multiply 5x and 1 which is 5x
and you subtract 5x by -5x which is 0
finally you multiply 1 and -1 which is -1 and you put it all together which is 25x^2 -1