Factorising the Difference of Two Squares

Question 1:

x2 100
x + 10 x 10

Question 1:

x2 36
x + 6 x 6

Question 1:

x2 4
x + 2 x 2

Question 1:

x2 81
x + 9 x 9

Question 1:

16 x2 81
4 x + 9 4 x 9

Question 1:

25 x2 64
5 x + 8 5 x 8