SOLUTION: Hi, how do you work out this question? A rectangular painting is to have a total area (including the frame) of 1200 cm2. The painting is 30 cm long and 20 cm wide, find the width o

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: Hi, how do you work out this question? A rectangular painting is to have a total area (including the frame) of 1200 cm2. The painting is 30 cm long and 20 cm wide, find the width o      Log On


   

Question 773694: Hi, how do you work out this question? A rectangular painting is to have a total area (including the frame) of 1200 cm2. The painting is 30 cm long and 20 cm wide, find the width of the frame. Thanks so much!
Answer by josgarithmetic(39613) About Me  (Show Source):
You can put this solution on YOUR website!
Length of picture without frame, 20
Height of picture without frame, 30
x is outer length of frame
y is outer height of frame
w is width of frame around picture
xy=1200
x=30%2B2w
y=20%2B2w
highlight%28%2830%2B2w%29%2820%2B2w%29=1200%29 SOLVE FOR w.

Factoring and dividing both sides by 4,
%28w%2B15%29%28w%2B10%29=300
w%5E2%2B25w%2B150-300=0
highlight%28w%5E2%2B25w-150=0%29 FACTORABLE.
%28w%2B30%29%28w-5%29=0
highlight%28w=5%29
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