2) (4-x)²-(x-3)² = [4-x - (x-3)] . (4-x+x-3)
= (4-x - x+3). (4-x+x-3)
= (7-2x)1
= 7-2x
4) (x-3)² - (x-4)(x+4) = (x-3)² - (x²-y²)
= x²-2.x.3+3²-x²+y²
= x²-6x+3²-x²+y²
= -6x+9+y²
6) (2x+3)²-(2x-3)(2x+3)
= (2x)²+2.2x.3 + 3²-[(2x)²-3²]
= 4x²+12x+9-4x² + 9
=12x+18
