EXPLANATION
Rectangle:
Area = 144x^2 square meters
Width= 12x meters.
As we know, the area of a rectangle is given by the following formula:
AREA = 2*(Length + Width)
Replacing values in the equation:

Applying distributive property:

Adding similar terms:

Dividing both sides by 2:

Now, we need to solve this equation:
Applying exponent rule: a^(b+c) = a^b*a^c
x^4=x*x^3
=74x^3x-12
Rewriting 12 as 2*6
Rewriting 74 as 2*37
=2*37x^3x-2*6x
Factor out common term 2x:
=2x(37x^3-6)
Answer: Length is 2x(37x^3-6)