Solve by factoring!

2

2

2

1. 8 12 0

2. 2 3 9 0

3. 3 10 8

x x

x x

x x

Solving Quadratic

Equations by Taking Square

Roots

Solving with Square Roots

1. Get x2 or binomial squared by itself

2. Take the square root of BOTH sides of the equals sign

3. Don’t forget the sign4. Simplify

Solve by Taking Square Roots

21. 4 0x

2x i

Solve by Taking Square Roots

212. 3 12

2x

3 2x

Solve by Taking Square Roots

23. 2x 338 0

13x i

Solve by Taking Square Roots

214. 3 4

7x

7x

Solve by Taking Square Roots

25. 9 243x

3 3x i

Solve by Taking Square Roots

236. 2 5

5x

5x

Solve by Taking Square Roots

27. 5 4 125x

1 and 9x

Solve by Taking Square Roots

21

8. 4 1 53x

4 3 2x

Falling Objects!Use h = -16t2 + h0

Height of the

object AFTER it

has fallen

TIME after the object

has dropped

Object’s

INITIAL height

ExampleThe tallest building in the USA is in Chicago, Illinois. It is 1450 ft. tall. How long would it take a penny to drop from the top of the building to the ground?

1450160 2 t0

216 hth

2161450 t2625.90 t2625.90 t

seconds 52.9t

For a period of 48 months, the average monthly operating costs for a small business C (in dollars) is approximated by the model C = 0.55t2 + 550 where t is the number of months. During which month was the average operating cost $1430?

2880 0.55t21430 0.55 550t

21600 t21600 t

40t months

Example

ApplicationThe formula for the volume of a cylinder is V = .

Solve the formula for r.

2r h

Homework

Practice

Sheet