Question

Which expressions are differences of squares?

Select each correct answer.
 


x^2−169

t^2−4

a^2+1

h^2−20

Answer 1

x²-169 and t²-4 are the two answers.
169=13², 4=2²

20 is not a square number, so not D.
1 is a square number, but C shows the sum, not difference, so not C either.