# The price of discount airline ticket starts at $150 and increases by$30 each week. Which algebraic expression models this situation?

Mar 24, 2018

So we start at $150$ dollars. Then we add on $30$ dollars per week.

So we have $150$ plus $30$, which changes each week. By the second week it's $150 + 60$, week three has $150 + 90$.

So our equation is $150 + 30 x$

Mar 24, 2018

$150 + 30 x$

#### Explanation:

Since the airline ticket begins at $150$, that is the beginning of the equation:

$150$

But the ticket increases by $30 every week, so let's start out with that. The first week, the equation is: $150 + 30$The second week it would be: $150 + 30 \left(2\right) \rightarrow 150 + 60$The third week it would be: $150 + 30 \left(3\right) \rightarrow 150 + 90$The fourth week it would be: $150 + 30 \left(4\right) \rightarrow 150 + 120$So you can see a pattern. Every week you multiply $30$by the week that it is. We can write this fact algebraically by saying: $150 + 30 \left(x\right)$where $x\$ is the week.