In Lesson 6-3, you solved linear systems using elimination. The same technique can be applied to systems of linear and quadratic equations.
Recreation Since opening day, attendance at Pool A has increased steadily, while attendance at Pool B first rose and then fell. Equations modeling the daily attendance y at each pool are shown below, where x is the number of days since opening day. On what day(s) was the attendance the same at both pools? What was the attendance?
Pool A:
Pool B:
Know | Need | Plan |
---|---|---|
Equations giving the attendance at each pool | The day(s) when the attendance was the same | Use elimination to solve the system formed by the equations. |
Step 1 Eliminate y.
Step 2 Factor and solve for x.
Step 3 Find the corresponding y-values. Use either equation.
The pools had the same attendance on days 4 and 15. On Day 4, each pool had 204 people. On Day 15, each pool had 424 people.