Gerald purchased 55 paving stones to use in his garden. the graph shows points representing the number of stones left to place at several different times while gerald is working.

Which statement about perfect cubes is true

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.

Determine whether the statement is true or false