d=5 s9= 75 a=? a9= ?
Answers
Answered by
6
a=1/4
a9=4.25
Sn=n/2[2a+(n-1)d]
9=9/2[2×a+(9-1)5]
9=18/2a[8×5]
9=9a[40]
9=36a
a=9/36
a=1/4
an=a+(n-1)d
1/4+(9-1)5
1/4+(8×5)
1/4+40
1+160/4
161/4
a9=4.25
hope may help you
thank you ☺️
Answered by
0
Answer:
Step-by-step explanation:
d=5,s
9
=75
s
9
=
2
9
[2a+(9−1)5]
75=
2
9
[2a+40]
150=9[2a+40]
150=18a+360
150−360=18a
−210=18a
18
−210
=a
a=
3
−35
a
9
=a+(9−1)5
a
9
=
3
−35
+40
a
9
=
3
−35+120
a
9
=
3
−85
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