Question

A finite arithmetic sequence has 12 terms. The last term Is 100 and the common difference is 3. What is the first term

Answer 1

Answer:

the first term is 67

Step-by-step explanation:

A finite arithmetic sequence has 12 terms. The last term Is 100 and the common difference is 3.

the formula for nth term is

$a_n = a_1 +(n-1)d$

Equation for 12th term is

$a_{12} = a_1 +(12-1)d$

a_12 is the last term, a1 is the first term and d is the common difference

a12= 100, d= 3

$100 = a_1 +(11)3$

$100 = a_1 +33$

Subtract 33 from both sides

a_1= 67

So the first term is 67