1. 13-7 Warm-ups
Solve. 1. 2.

2. 13-7 Using Quadratic Equations
Chapter 13

3. Example 1
A picture frame measure 20 cm by 14 cm. The picture, inside the frame, takes up 160 square centimeters. Find the width of the frame.
14 cm
160 cm2
20 cm

4. Example 1 Solve. Check: When x = 15, 20 – 2x = –10, and 14 – 2x = –16.
The width of the picture frame
is 2 cm.

5. Try This
a. A rectangular garden is 80 m by 60 m. Part of the garden is torn up to install a strip of lawn of equal width around the garden. The new area of the garden is 800 m2. How wide is the strip of lawn?

6. Example 2
The hypotenuse of a right triangle is 6 cm long. One leg is 1 m longer than the other. Find the lengths of the legs. Round to the nearest hundredth. 6 x
X+1

7. Example 2
Solve.
Since we cannot factor,
we use the quadratic formula.

8. Example 2 or
One leg is about 3.72 m and the other is about 4.72m long.

9. Try This
b. The hypotenuse of a right triangle is 4 cm long. One leg is 1 cm longer than the other. Find the lengths of the legs. Round to the nearest tenth.