given d=5 sa =75,find a and a9
Answers
Answered by
1
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
Answered by
0
d=5,s⁹ =75
s⁹ = 9 [2a+(9−1)5]
2
75= 9 [2a+40]
2
150=9 [2a+40]
150= 18a+360
150−360=18a
−210=18a
−210 =a
18
a= −35
3
a⁹ =a+(9−1)5
a⁹ = −35 + 40
3
a⁹ = − 35 + 120
3
a⁹ = − 85
3
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