[tex]width=8+x+x=8+2x\\length=9+x+x=9+2x\\\\Area:A=width\cdot length\\\\A=(8+2x)(9+2x)=(8)(9)+(8)(2x)+(2x)(9)+(2x)(2x)\\\\=72+16x+18x+4x^2=4x^2+34x+72\\\\A=75ft^2\\therefore\\\\4x^2+34x+72=75\ \ \ \ |subtract\ 75\ from\ both\ sides\\\boxed{4x^2+34x-3=0}[/tex]
