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Expand and simplify

5 (p+6) - 2 (3p+4)
and
7 (k-2) - 3 (2k-5)
Find the nth term for each sequence
5,9,13,17,21

1,8,15,22,29

10,6,2,-2,-6

Please help​

1 Answer

6 votes

Answer:

A) -p + 38

B) k + 1

C) a_n = 4n + 1

D) a_n = 7n - 6

E) a_n = 14 - 4n

Explanation:

A) 5(p + 6) - 2(3p + 4)

Multiply out the bracket to get;

5p + 30 - 6p + 8

>> -p + 38

B) 7(k - 2) - 3(2k - 5)

Multiply out the bracket to get;

>> 7k - 14 - 6k + 15

>> k + 1

C) Sequence is;

5, 9, 13, 17, 21

This is clearly an AP(arithmetic progression) because the difference between each term is 4.

Formula for nth term of an AP is;

a + (n - 1)d

Where d is difference and a is first term

Thus;

a_n = 5 + (n - 1)4

a_n = 5 + 4n - 4

a_n = 4n + 1

D) Sequence is 1, 8, 15, 22, 29.

This is also an AP.

Difference is 7.

Thus,nth term is;

a_n = 1 + (n - 1)7

a_n = 1 + 7n - 7

a_n = 7n - 6

E) 10, 6, 2, -2, -6

This is also an AP.

Difference is -4

Thus,

a_n = 10 + (n - 1)(-4)

a_n = 10 - 4n + 4

a_n = 14 - 4n

User Ayls
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