Systems of equations

1. Systems of equations Chapter 8

2. 8.1 – solving systems of equations graphically Chapter 8

3. Systems of equations If you have a system of equations, you can solve it by graphing both equations. Consider if you were given one quadratic equation and one linear equation: Consider if you were given two quadratic equations:

4. example Solve the following system of equations graphically: 4x – y + 3 = 0 2x2 + 8x – y + 3 = 0 If we want to graph the equations, what do we need to solve for in each equation? To find the intersection points use TRACE  INTERSECT 4x – y + 3 = 0  4x + 3 = y 2x2 + 8x – y + 3 = 0  2x2 + 8x + 3 = y Points of intersection are (0, 3) and (–2, –5)

5. Try it Solve the system graphically, and verify your solution: x – y + 1 = 0 x2 – 6x + y + 3 = 0

6. example Solve: 2x2 – 16x – y = –35 2x2 – 8x – y = –11 • 2x2 – 16x – y = –35 • 2x2 – 16x + 35 = y 2x2 – 8x – y = –11  2x2 – 8x + 11 = y The intersection point is at (3, 5).

7. example Suppose that in one stunt, two Cirque du Soleil performers are launched toward each other from two slightly offset seesaws. The first performer is launched, and 1 s later the second performer is launched in the opposite direction. They both perform a flip and give each other a high five in the air. Each performer is in the air for 2 s. The height about the seesaw versus time for each performer during the stunt is approximated by the parabola as shown. Their paths are shown on a coordinate grid. Determine the system of equations that models their height during the stunt. b) Solve the system.

8. example

9. Pg. 435–439, # 3, 4, 5, 6, 8, 9, 11, 13. Independent Practice

10. 7.2 – solving quadratic equations by factoring Chapter 7