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Define x :
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Let the width be x
Width = x
Length = 4x + 7
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Formula :
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Perimeter = 2 (Length + Width)
Perimeter = 74
2(4x + 7 + x) = 74 // sub length and width into the equation
2(5x + 7) = 74 // combine like terms
10x + 14 = 74 // Apply distributive property
10x = 60 // Take away 14 from both sides
x = 6 // Divide by 10 on both sides
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Find Length and Width :
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Width = x = 6mm
Length = 4x + 7 = 4(6) + 7 = 31mm
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Answer: The length is 31mm and its width 6mm.
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