Problem:
What is the value of
(3x−2)(4x+1)−(3x−2)4x+1
when x=4 ?
Answer Choices:
A. 0
B. 1
C. 10
D. 11
E. 12
Solution:
Since
(3x−2)(4x+1)−(3x−2)4x+1=(3x−2)(4x+1−4x)+1=(3x−2)⋅1+1=3x−1
when x=4 we have the value 3⋅4−1=11.
The problems on this page are the property of the MAA's American Mathematics Competitions