2.4 Algebra 2cc Section 2.4 Solve quadratic equations by completing the square

1. 2.4 Algebra 2cc Section 2.4Solve quadratic equations by completing the square Note: you can’t solve x2 + 6x + 2 = 0 by factoring or by square roots… To solve a quadratic equation by completing the square Make the leading coefficient one Isolate the constant Add the square of ½ the linear coefficient Factor – square root-solve Solve by completing the square. x2 + 6x + 2 = 0

2. Solve by completing the square 3x2 – 6x + 12 = 0 ½ x2 + 5x - 16 = 0

3. On dry asphalt, the distance d in feet needed for a car to stop is given by d = .05s2 + 1.1s where s is the car’s speed in miles per hour. What speed limit should be posted on a road where drivers round a corner and have 80 feet to stop?

4. When a gray kangaroo jumps, its path through the air can be modeled by y = -.0267x2 + .8x where x is the kangaroo’s horizontal distance traveled in feet and y is its corresponding height in feet. How far has the kangaroo traveled horizontally when it is 4 feet high?

5. assignment • Page 287 • Problems 4-14 even, 48-72 even, 85,86,90