A ) ( x - 3 )( x + 1 ) [ not perfect ]
B ) ( x + 5 - √5 )( x + 5 + √5 ) [ n p ]
C ) ( x + 2 + 2√2 )( x + 2 - 2√2 ) [n p ]
D ) ( x - 6 )( x - 6 ) = ( x - 6 )^2 [ perfect ]
Thus the correct answer is option D .
Well 40 times 6 is 240 which means that you don't have to round.
