Question

Which of the following is equivalent to (a + b)(c + d)?

A. ac + 2bc + bd
B. a + bc + d
C. ac + ad + bc + bd
D. ac + bd

Answer 1

C. ac + ad + bc + bd

Explanation:

1. FOIL (first, inner, outer, last)
2. a * c = ac
3. b * c = bc
4. a * d = ad
5. b * d = bd
6. Combine them and rearrange = ac + ad + bc + bd