The total garden including the border has dimension 3x by x where x is the width in inches.
The dimensions of the growing area are reduced by 6 inches (3 inches on each side) so its dimensions are 3x-6 by x-6 and the equation for the area is 180=(3x-6)(x-6)=3x²-24x+36, answer option 2.
(Although the question doesn’t ask for it we get the equation 3x²-24x-144=0, which reduces to x²-8x-48=0=(x-12)(x+4), so x=12 inches and the dimensions are 12 by 36 inches, with the growing area 6 by 30 inches.)