1. Warm Up for Section 3.3
Factor:
(1). x2 – 49
(2). x2 + 6x – 16
(3). a2 – 7a + 12
(4). 6x2 + x – 15
(5). 3xa – 2xc + 6ay – 4yc

2. Answers for Warm Up for Section 3.3
Factor:
(1). x2 – 49 = (x + 7) (x – 7)
(2). x2 + 6x – 16 = (x + 8 )(x – 2)
(3). a2 – 7a = (a – 3)(a – 4)
(4). 6x2 + x – 15 = (3x + 5)(2x – 3)
(5). 3xa – 2xc + 6ay – 4yc = (x + 2y)(3a – 2c)

3. Solving Quadratic Equations by Taking Square Roots
Section 3.3
Essential Question: How do I solve quadratic equations by using square roots?

4. Rules for solving by taking the square root:
Isolate the squared variable.
Take the square root of both sides.
Do not forget that you will usually have 2 answers!

5. Solve the equation by taking square roots: (1). x2 – 5 = 0
Add 5 to both sides
x2 = 5
x =
Take square root of each side
Solution set:

6. Solve the equation by taking square roots: (2). 2x2 – 3 = 93
Add 3 to both sides
x2 = 48
Divide both sides by 2
x =
Take square root of each side
x =
Simplify radical
Solution set:

7. Solve the equation by taking square roots: (3). ½(y – 2)2 + 1 = 4
Subtract 1 from both sides
(y – 2)2 = 6
Multiply both sides by 2
(y – 2) =
Take square root of each side
y =
Add 2 to both side
Solution set:

8. Solve the equation by taking square roots: (4). 2(y2 – 5) = -y2 – 1
Distribute
3y2 – 10 = – 1
Add y2 to both sides
3y2 = 9
Add 10 to both sides
y2 = 3
Divide both sides by 3
y =
Take square root of both sides
Solution set:

9. Try these with your partner:
(5). x2 – 19 = 0 (6). 5(x – 4)2 = 125
(7). 3(x – 5)2 = (8).
(9). 3(x – 3)2 + 2 = 26

10. 10. The edge of a cube has the measure of (x + 5) units
10. The edge of a cube has the measure of (x + 5) units. The surface area of the cube is 864 square units. What is the measure of the edge of the cube?
6(x + 5)2 = SA
6(x + 5) 2 = 864
(x + 5) 2 = 144
x + 5 = ± 12
x = -5 ± 12
x = -17, 7
Edge = x + 5 = = 12
12 units