Sarah wants to hang a mirror in her room but the mirror and frame must not have an area larger than 15 square feet. The mirror is 3 feet wide and 4 feet long. Which quadratic equation represents the area of the mirror and frame combined? (The frame must have equal width of x on each side.)

3x2 + 14x − 2 = 0
4x2 + 14x − 3 = 0
x2 + 12x − 14 = 0
2x2 + 7x − 14 = 0

Question

Sarah wants to hang a mirror in her room but the mirror and frame must not have an area larger than 15 square feet. The mirror is 3 feet wide and 4 feet long. Which quadratic equation represents the area of the mirror and frame combined? (The frame must have equal width of x on each side.)

 	
	3x2 + 14x − 2 = 0
	4x2 + 14x − 3 = 0
	x2 + 12x − 14 = 0
	2x2 + 7x − 14 = 0

anonymous · Answer

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anonymous · Answer

Well to find the area of a rectangle we do
 S + S x 2    or    s•s + s•s 

so we have 3 +4 x 2 = x 
or 3 x 3 + 4 x 4 = x 

@lgbasallote Right-o?

anonymous · Answer

So far at least haha obviously not the full answer yet but I want to make sure I'm on the right track.

anonymous · Answer

umm i really dont know but if you get the wrong answer no big deal :)

anonymous · Answer

lol no problem xD

anonymous · Answer

Mmm, I don't quite see what you're saying there. I don't think it's right.

anonymous · Answer

what did you get?

anonymous · Answer

Well we have to find the initial area before doing the next part xD lol idk @nick SmoothMath is a dollface he's really good at helping :D I'll shut up now :x

anonymous · Answer

That's a thought, Becca, but this will work better.
First, Nick, simply draw a picture, like this
|dw:1341586226088:dw|
See how I drew the mirror, 3X4, and then the frame around it has a width of x?