Multiplying Binomials

highlight term

F

O

I

L

a

b

c

d

(a x + b) (c x + d) =

(2 x + 3) (4 x + 5) =

(2 x) (4 x) + (2 x) (5) + (3) (4 x) + (3) (5) =

8

2

x

+ 10 x + 12 x + 15 =

8

2

x

+ 22 x + 15

You can use the FOIL method to multiply out binomials of the form

(ax+b)(cx+d)

. FOIL stands for First-Outer-Inner-Last. First means multiply the first terms

ax

and

cx

; Outer means multiply

ax

and

d

; Inner gives the term

bcx

; and finally Last gives the term

bd

.