=
=(a³ + b³)(a ³ − f ³)
-
=(a+b)(a ² − ab + b ²)(a − b )(a² + ab + b ²)
=(a+b)(a−b)(a
5a6-b6
² + ab + b ²)(a ² - ab + b ²)
= (a ²)³—(6²)³
= (a²_b²)(a¹ + a²f²+b¹)
=(a+b)(a−b){(a² + b ²)² — (ab)²}
=(a+b)(a−b)(a² + ab + b²)(a²- ab + b ²)
(3) (a²-1)(b ²-1)-4ab
=a²f²_b²-a²+1-4ab
= (a ²b² - 2ab + 1) − (a ² + 2ab + b ²) L
=(ab − 1)²(a+b)²
={(ab−1)+(a+b)}{(ab − 1)−(a+b)}
= (ab+a+b−1)(ab-a-b− 1)
(4) x² + 4xy-y² +4
= x¹ + 4xy-y² +4+4x²−4x²
= (x 4 +4x²+4) — (4x² — 4xy + y²)) = \\
=(x²+2)²-(2x−y)²
={(x²+2)+(2x−y)}{(x²+2) — (2x −y)}
=(x²+2x−y+2)(x² −2x+y+2)
