Answer
See below.
Work Step by Step
According to the exercise:
$a_0=2,a_1=4$
$a_2=a_1-a_0=4-2=2$
$a_3=a_2-a_1=2-4=-2$
$a_4=a_3-a_2=-2-2=-4$
$a_5=a_4-a_3=-4-(-2)=-2$
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