Question

Tom wants to hang a mirror in his room. The mirror and frame must have an area of 14 square feet. The mirror is 3 feet wide and 4 feet long. Which quadratic equation can be used to determine the thickness of the frame, x?

Answer 1

A = L x W (mirror and frame)
do we assume uniform thickness of frame?

Answer 2

Yes.

Answer 3

\[14 = (L) \times (W)\]
\[14 = (Mirror L + Frame L) \times (Mirror W + Frame W)\]
\[14 = (4 + x) \times (3 + x)~~\text{if uniform thickness}\]
\[\text{use FOIL to expand}~~(4 + x) (3 + x)~~\]
can u solve from here @BasedGod1122 ???

Answer 4

12+4x+3x+x^2 ?

Answer 5

yep, that's ur quadratic, and that = 14

Answer 6

no, that equals 14, if u take 14 from both sides, u can find the zero's...

Answer 7

x^2 + 7x - 2 = 0
solve for x to find thickness

Answer 8

How do I solve for x? Walk me through the steps?

Answer 9

x = 0.27491721763537484861834240347306 feet

Answer 10

do you know the quadratic equation...?

Answer 11

http://www.calctool.org/CALC/math/functions/quadratic.png

Answer 12

This is a multiple choice question. My choices are:

4x2 + 14x - 2 = 0

3x2 + 10x - 14 = 0

2x2 + 12x - 14 = 0

x2 + 7x - 14 = 0

Answer 13

use the formula

\[\frac{ -b +- \sqrt{b ^{2}-4ac} } {2}\]

Answer 14

none of the above options work, as @kx2bay said, the quadratic equation comes down to
x^2 + 7x - 2 = 0
so non of ur answers match...?

Answer 15

yes jack is right
if you substitute x = 0.27492 in jacks formula above
14=(4+x)×(3+x)
u get 14=14

Answer 16

So which choice do i select

Answer 17

none of the above choices is correct, I'd say they made a typo with the 4th choice
x2 + 7x - 14 = 0
where -14 should be -2
so go with this choice

Answer 18

Thank you, friend. You've really helped me out. I hope that you have a good night.

Answer 19

thanks you too, its actually day light here in melbourne australia ;)