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A(1)= -2
a(n)=a(n-1)-5
whats the 4th term in the sequence?

2 Answers

5 votes
Hello,

A_1=-2\\ A_2=A_1-5=-2-5=-7\\ A_3=A_1-2*5=-2-2*5=-12\\ A_4=A_1-3*5=-2-3*5=-17\\
User Nisanio
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5 votes

Answer:

The fourth term in the sequence is -17

Explanation:

To find the 4th term of the sequence, we will simply follow the steps below;

a(1) = -2

a(n) = a(n-1)-5

We will find the value of the sequence when n = 1, n= 2 n =3 n=4

The first one has been done for us, so we have the first term to be a(1) = -2

The next thing to do, is to find the second term, ie. when n=2

a(n) =a(n-1)-5

a(2) =a(2-1)-5

=a(1) - 5

but a(1) = -2

a(2) =a(1) - 5

=-2-5

=-7

a(2) = -7

next is to find the third term, ie. when n=3

a(n) =a(n-1)-5

a(3) =a(3-1)-5

=a(2) - 5

but a(2) = -7

a(3) =a(2) - 5

=-7-5

=-12

a(3) = -12

next is to find the fourth term, ie. when n=4

a(n) =a(n-1)-5

a(4) =a(4-1)-5

=a(3) - 5

but a(3) = -12

a(4) =a(3) - 5

=-12-5

=-17

a(4) = -17

Therefore, the fourth term in the sequence is -17

User Sachin Mandhare
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6.7k points