1 . (a – b)² = a² – 2ab + b² <- folosind formula efectuati :
a) (x - 4)²
......
e) (3 - x)²

2 . (a – b)(a + b) = a² – b² <- efectuati .
a) ( x+3)(x-3)
....
g) (4a-3b)(4a+3b)
.....
h) (2x-5y)(2x+5y)