# How do you find a_43 given 5, 9, 13, 17,...?

Dec 13, 2016

See explanation.

#### Explanation:

From the given terms you see that the first term of the sequence is ${a}_{1} = 5$ and the common difference is $d = 4$, so to calculate the fourty third term you can use the formula:

## ${a}_{n} = {a}_{1} + \left(n - 1\right) \times d$

If we substitute the given data we get:

${a}_{43} = 5 + \left(43 - 1\right) \times 4 = 5 + 42 \times 4 = 5 + 168 = 173$.

Answer: The 43rd term is ${a}_{43} = 173$