Question

5)Solve 2x2 +6x = 4 by completing the square.

6)Solve 3x2 - 6x- 24 = 0 using the quadratic formula.

7)The area of a circle is 25 in^2. What is the radius, including the units? Area of a circle is ¢³r^2.

8)The 3 sided triangle has an area of 14 in^2. Determine the lengths of the sides of the triangles. Remember that the area of a triangle is ¨ö bh. Bottom length is x+3 the side length is x

Answer 1

5. 2x2 + 6x = 4
Divide Fq by 2:
x2 + 3x = 2
x2 + 3x + (3/2)^2 = 2 + 9/4
x2 + 3x + 9/4 = 8/4 + 9/4 = 17/4
x2 + 3x + 9/4 - 17/4 = 0
x2 + 3x -8/4 = 0
x2 + 3x - 2 = 0
Use Quadratic Formula:
X = 0.562, and -3.562.

6. 3x2 - 6x - 24 = 0
Divide Eq by 3:
x2 - 2x - -8 = 0
Solve using Quadratic formula:

7. A = pi*r^2 = 25in^2
3.14r^2 = 25
r^2 = 25/3.14 = 7.96
r = 2.82 Inches.

8. A = (bh)/2 = 14 In^2
((x+3)x)/2 = 14
Multiply Eq by 2:
(x+3)x = 28
x^2 + 3x = 28.
x^2 + 3x - 28 = 0
(x+7)(x-4) = 0
x+7 = 0
x = -7.

x-4 = 0
x=4.

Solution set: X = -7, and 4.