For ?'s 3-6: A 3 ft. wide walk is built around a rectangular garden 18 ft. by 12 ft. Find the area of the garden.
Group of answer choices

162 sq. ft

216 sq. ft

245 sq. ft

206.4 sq. ft

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.