Question

Find the first, fourth, and tenth terms of the arithmetic sequence described by the given rule. A(n) = 1 + (n - 1) (-5.7)

A)1, –21.8, –56

B)–5.7, –21.8, –51.3

C)0, –17.1, –51.3

D)1, –16.1, –50.3

Answer 1

well the first term = 1 because (n - 1) = 0 for the first term
So its either A or D
4th term = 1 + (4 - 1)(-5.7 = 1 + 3*-5.7 = -17.1

Its C

Answer 2

D) 1, -16.1, -50.3

Explanation:

For calculate the first term of the sequence we replace n by 1 in the equation, then:

A(n)=1+(n-1)(-5.7)

A(1)=1+(1-1)(-5.7)

A(1)=1

At the same way we can calculate the fourth term of the sequence replacing n by 4 in the equation, then:

A(n)=1+(n-1)(-5.7)

A(4)=1+(4-1)(-5.7)

A(4)=1 + 3*(-5.7)

A(4)=-16.1

Finally, the tenth term of the sequence can be calculate replacing n by 10, so:

A(n)=1+(n-1)(-5.7)

A(10)=1+(10-1)(-5.7)

A(10)= 1 + 9*(-5.7)

A(10)=-50.3

Then, the first, fourth and tenth term of the sequence is 1, -16-1 and -50.3 respectively.