Annie is framing a photo with a length of 6 inches and a width of 4 inches. The distance from the edge of the photo to the edge of the frame is x inches. The combined area of the photo and frame is 63 square inches.
First, draw and label a picture based on the description (note: you certainly can do better than WyzAnt Answers Forum allows):
^ XXXXXXX
| L X111111X
| E X222222X
| N X333333X
| X444444X
V XXXXXXX
A) write a quadratic function to find the distance from the edge of the photo to the edge of the frame. You must show your work to receive credit
"combined area of the photo and frame is 63 square inches" = length*width = (x+6+x)*(x+4+x) = 63
(2x+6)(2x+4) = 63 [combine terms]
4x2 + 8x + 12x + 24 = 63 [use F-O-I-L]
4x2 + 20x - 39 = 0 [combine terms; and subtract 63 from both sides]
b) what is the value of x? Must show work to receive credit
4x2 + 20x - 39 = 0
(x-1.5)(x+6.5) = 0 [either factor or use quadratic formula]
The multiplicative property of zero demands that either x=1.5, x=-6.5, or both.
-6.5 is not possible measurement
x=1.5
c) how wide are the photo and frame together? Must show work to receive credit
width of photo = 4 in; width of photo and frame together = 1.5+4+1.5 = 7 inches
Also, length of photo = 6 in; length of photo and frame together = 1.5 + 6 +1.5 = 9 inches
Check (very important):
Does width*length = 63 square inches ?
(7 inches)*(9 inches) = 63 square inches ?yes