Answer
The first six terms are:
$300, 210, 120, 30, -60, -150$
Work Step by Step
The next five terms f the sequence can be found by adding the common difference to obtain:
$a_1=300
\\a_2=300+(-90)=210
\\a_3=.210+(-90)=120
\\a_4=120+(-90)=30
\\a_5=30+(-90)=-60
\\a_6=-60+(-90)=-150
