1. (x + 3)(1 – 2x) = ?
(x + 3)(1 – 2 x) = x – 2 x ² + 3 – 6 x
= –2 x ² – 5 x + 3
 a(b + c) = ab + ac
 (a + b)(c + d) = ac + ad + bc + bd
 (a + b)² = a² + 2ab + b²
 (a – b)² = a² – 2ab + b²
 (a + b)(a – b) = a² – b²

2. 

a b a b
a  b a b
a b a b
a  b a b

4. t

5.  n
 n
n
