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Answer: The width is 7 meters. The length is 10 meters.
Step-by-step explanation: Area = Length × width
Length is 2w - 4
Substitute that value for length, then solve for w.
70 = w(2w - 4)
70 = 2w² - 4w reorganize to quadratic equation form
2w² - 4w -70 = 0 These are All even numbers; factor out 2 (divide all by 2)
w² - 2w - 35 = 0 factor this
(w - 7)(w + 5) set each factor = 0 and calculate the value of w.
w+5=0 w= -5 (disregard this one because dimensions of real rectangles can't be negative)
w - 7 = 0 w = 7 The width is 7
Substitute into the original expressions to get the value of Length.
2(7) -4 = L 14 - 4 = L The Length is 10.
Check by substituting into the original equation:
w × 2w -4 = 70
7 × 2(7) -4 = 70
7 × 10 = 70 TRUE!
w
Dimensions of the rectangle are length=10 meter and width= 7 meter
What is Rectangle?
A rectangle is a quadrilateral with four right angles.
Given,
The length of a rectangle is 4 meter less than twice its width
Consider,
l is the length of the rectangle
w is the width of the rectangle
l=2w-4
Area of the rectangle = Length × Width
70=l × w
Substitute the value of l is the second equation
70=(2w-4)×w
[tex]2w^{2} -4w=70\\2w^{2} -4w-70=0[/tex]
Take 2 outside
[tex]2(w^{2}-2w-35)=0\\ w^{2} -2w-35=0\\(w+5)(w-7)=0[/tex]
w=7,-5
Hence w wont be negative value
Therefore w=7 meter
Then,
l×w=70
[tex]l=\frac{70}{7}\\[/tex]
l=10 meter
Hence, the dimensions of the rectangle are length=10 meter and width= 7 meter
Learn more about rectangle here
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