SOLUTION: The length of a poster is 10cm longer than its width. If the area of the poster is 1200cm2, what is the width of the poster. Please can someone help this quad word problem is dr

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Question 376108: The length of a poster is 10cm longer than its width. If the area of the poster is 1200cm2, what is the width of the poster.
Please can someone help this quad word problem is driving me nuts.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The length of a poster is 10cm longer than its width.
:
If the area of the poster is 1200cm2, what is the width of the poster.
:
L = the length
W = the width
:
Write an equation for each statement;
:
"The length of a poster is 10cm longer than its width."
L = W+10
:
"the area of the poster is 1200cm2,"
L * W = 1200
:
what is the width of the poster.
: Using the 1st equation replace L with (W+10) in the 2nd equation
(W+10) * W = 1200
W^2 + 10W = 1200
A quadratic equation
W^2 + 10W - 1200 = 0
This can be factored to
(w+40)(w-30) = 0
The positive solution
w = 30 cm is the width
then
L = 30 + 10
L = 40 cm is the length
:
:
Confirms this with the area: 40 * 30 = 1200