Answer:
Pakibrainliest po ng answers ko
Step-by-step explanation:
Formula :
[tex] a_{n} = a_{1} + (n \: - 1)(d)[/tex]
1.
[tex] a_{15} = 20 + (15 - 1)(4) \\ = 20 + (14)(4) \\ = 20 + 56 \\ = 76[/tex]
2.
[tex] a_{7} = a_{1} + (7 - 1)(3) \\ 23 = a_{1} + (6)(3) \\ 23 = a_{1} + 18 \\ a_{1} = 23 - 18 = 5[/tex]
3.
[tex] 105 = 15 + (n - 1)(10) \\ 105 = 15 + 10n - 10 \\ 10n = 105 - 15 + 10 \\ 10n= 100 \\ n = 10[/tex]
4.
[tex] a_{5} = a_{1} + (n - 1)(d) \\ 1 = - 7 + (5 - 1)(d) \\ 4d = 1 + 7 \\ 4d = 8 \\ d = 2[/tex]
5.
[tex] a_{20} = - 3 + (20 - 1)( - 9) \\ = - 3 + (19)( - 9) \\ = - 3 - 171\\ = - 174[/tex]
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Answers & Comments
Answer:
Pakibrainliest po ng answers ko
Step-by-step explanation:
Formula :
[tex] a_{n} = a_{1} + (n \: - 1)(d)[/tex]
1.
[tex] a_{15} = 20 + (15 - 1)(4) \\ = 20 + (14)(4) \\ = 20 + 56 \\ = 76[/tex]
2.
[tex] a_{7} = a_{1} + (7 - 1)(3) \\ 23 = a_{1} + (6)(3) \\ 23 = a_{1} + 18 \\ a_{1} = 23 - 18 = 5[/tex]
3.
[tex] 105 = 15 + (n - 1)(10) \\ 105 = 15 + 10n - 10 \\ 10n = 105 - 15 + 10 \\ 10n= 100 \\ n = 10[/tex]
4.
[tex] a_{5} = a_{1} + (n - 1)(d) \\ 1 = - 7 + (5 - 1)(d) \\ 4d = 1 + 7 \\ 4d = 8 \\ d = 2[/tex]
5.
[tex] a_{20} = - 3 + (20 - 1)( - 9) \\ = - 3 + (19)( - 9) \\ = - 3 - 171\\ = - 174[/tex]