If a and b are integers, find values such that a^2 - b^2 = 21.

Question

how would you calculate this?

Answer 1

a^2-b^2 = (a-b)(a+b)
since 21 = 3*7,
a-b = 3
a+b = 7
so,
a = 5, b = 2

Answer 2

thank you!!