Question 440412
A rectangular sheet of paper has an area of 204in. squared. Its dimensions are (x+4) by (x+9). What are the dimensions of the paper.
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since area is width times length:
204 = (x+4)(x+9)
FOIL the right:
204 = x^2+9x+4x+36
204 = x^2+13x+36
0 = x^2+13x-170
solve by applying the quadratic formula to get:
x = {8.1, -21.1}
throw out the negative solution leaving:
x = 8.1
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dimensions are:
12.1 inch by 17.1 inch
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details of quadratic follows:
*[invoke quadratic "x", 1, 13, -170 ]