Question 115211
let x="frame width"


the length of the collector (minus the frame on each end); multiplied by the width of the collector (minus the frame on each side)
___ is the exposed area of the collector (4 sq m)


(2.5-2x)(2-2x)=4 ___ 5-9x+4x^2=4 ___ 4x^2-9x-1=0