Answer:
The value of x is 5.
Step-by-step explanation:
We are given the following in the question:
Area of rectangle = 70 square miles
The sides of the rectangle are:
[tex]w = x, l = (2x+4)[/tex]
Area of rectangle =
[tex]A = l\times w[/tex]
Putting values, we get.
[tex]70 = (2x+4)x\\\Rightarrow 2x^2 + 4x - 70 = 0 \\\Rightarrow 2(x + 7)(x - 5) = 0\\\Rightarrow (x+7) = 0, (x-5) = 0\\\Rightarrow x = -7, x = 5[/tex]
Since, the value of x cannot be negative as it represents side of a rectangle.
Thus, the value of x is 5.
