Question 351137
Hi,
In your cousin's math problem: let x be the length, then the width would be(x/2 +20)
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Area = l*w
{{{x*(x/2 + 20) = 4800cm^2}}}
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{{{x^2/2 + 40x = 4800cm^2}}}
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multiply eacch term by 2
{{{x^2 + 40x = 9600cm^2}}}
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{{{x^2 + 40x - 9600cm^2 = 0}}} 
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factor
(x + 120)(x-80) = 0
x = 120 we cannot use
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x = 80cm is the width
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check your answer
{{{80cm* (80/2 + 20) = 80cm * 60cm = 4800cm^2}}}