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If the perimeter is 16 and the area is 15, what is the length and width? please show work!

User Cmill
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1 Answer

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Answer: x= 3 y=5

Explanation:

area=x⋅y=15 cm2

x=15y

perimeter=2x+2y=16 cm

Factoring out the 2 from the L.H.S. Then dividing both sides by 2:

2(x+y)=16

2(x+y)2=162

x+y=8

Substituting our value for x into the above equation:

15y+y=8

Multiplying both sides by y

:

y⋅(15y+y)=8y

y2+15=8y

y2−8y+15=0

The equation above is in the form

Ay2+By+C=0,

where A=1,B=−8,and C=15

The solution to the equation is shown below:

y=−B±B2−4AC√2A

Substituting the values for A, B, and C into the above equation:

y=−(−8)±(−8)2−4⋅1⋅15√2⋅1

Evaluating the above expression:

y=5 or y=3

Therefore, when y=5,x=3

and when y=3,x=5

User Shyam Prasad
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