Question 933360

Area = Length x Width


Then fill in the equation with what you know:


Area = 77
Length = X (unknown)
Width = X-4 (Width is 4 miles less than Length)


So your equation is:


X * (X-4) = 77
X^2 - 4X - 77 = 0


Then you use the quadratic equation to solve:


{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}


where a=1, b=-4, and c=-77


solving for X gives 2 answers, one negative and one positive. The negative one is irrelevant though because you will not have a "less than zero" length.


Your calculator or other online calculators can help solve the equation.


I get X = 11 or -7, and only 11 counts.


To check:


Using the equations at the very top:


Length = 11
Width = 7
Area = 77


Hope that helps :)