What polynomial identity will prove that 49-4=45

49 is a square given by 7x7 as is clear in your equation, 4 is a square given by 4x4 the operator given is - (minus) you have two squares, and a difference sign a^2 - b^2 = (a-b) (a+b) 7^2 - 2^2 = (7-2) (7+2) = (5) (9) = 45 it is the diffeernce of two squares