Question

the area of a rectangular wall of a barn is 30 square feet. It's length is 4 feet longer than twice width. Find the length and width of the wall of the barn

Answer 1

Width is 3 feet

Length is 10 feet

Explanation:

`LW=30\\L=2W+4\\\\(2W+4)W=30\\2W^2+4W=30\\2W^2+4W-30=0\\\\W=(-4\pm√(4^2-4(2)(-30)))/(2(2))=(-4\pm√(16+240))/(4)=(-4\pm√(256))/(4)=(-4\pm16)/(4)=-1\pm4=-5,3`

Since the width cannot be negative, we choose
`W=3` as the correct width. Therefore, the length would be
`L=2(3)+4=6+4=10`.