Question 95532
width=x
length=5+4x
(x)(5+4x)=80
5x+4x^2-80=0
4x^2+5x-80=0
using the quadratic equation we get;
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
x=(-5+-sqrt[5^2-4*4*-80])/2*4
x=(-5+-sqrt[25+1280])/8
x=(-5+-sqrt[1305])/8
x=(-5+-36.125)/8
x=(-5+36.125)/8
x=(-5+36.125)/8
x=31.125/8
x=3.89 answer.
x=(-5-36.125)/8
x=-41.125/8
x=-5.14 answer.