David wants to hang a mirror in his room. The mirror and frame must have an area of 8 square feet. The mirror is 2 feet wide and 3 feet long. Which quadratic equation can be used to determine the thickness of the frame, x?

2x2 + 14x - 2 = 0

3x2 + 10x - 8 = 0

4x2 + 10x - 2 = 0

x2 + 7x - 8 = 0

Question

Mathematics

Alec

5 March, 22:51

David wants to hang a mirror in his room. The mirror and frame must have an area of 8 square feet. The mirror is 2 feet wide and 3 feet long. Which quadratic equation can be used to determine the thickness of the frame, x?

2x2 + 14x - 2 = 0

3x2 + 10x - 8 = 0

4x2 + 10x - 2 = 0

x2 + 7x - 8 = 0

+2

Answers (1)

Know the Answer?

Rubi Gardner · Answer 1

The correct quadratic equation;

x2+7x-2=0

Working

Assuming the frame has a uniform thickness;

Then length of mirror and frame is 3+x and width 2+x

The area of mirror and frame area;

A=L*W

8 = (3+x) (2+x)

8 = (6+5x+x2)

Taking 8 to the Right hand side, we have:

x2+5x-2 = 0

David wants to hang a mirror in his room. The mirror and frame must have an area of 8 square feet. The mirror is 2 feet wide and 3 feet long. Which quadratic equation can be used to determine the thickness of the frame, x?2x2 + 14x - 2 = 03x2 + 10x - 8 = 04x2 + 10x - 2 = 0x2 + 7x - 8 = 0

David wants to hang a mirror in his room. The mirror and frame must have an area of 8 square feet. The mirror is 2 feet wide and 3 feet long. Which quadratic equation can be used to determine the thickness of the frame, x?

2x2 + 14x - 2 = 0

3x2 + 10x - 8 = 0

4x2 + 10x - 2 = 0

x2 + 7x - 8 = 0