Asked by Arabella

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

how would you calculate this?
Answered by oobleck
a^2-b^2 = (a-b)(a+b)
since 21 = 3*7,
a-b = 3
a+b = 7
so,
a = 5, b = 2
Answered by Arabella
thank you!!