The coefficients corresponding to k = 0, 1, 2, ..., 4 in the expansion of (x + y)4 are
A. 1, 4, 6, 4, 1
B. 1,4,6,6,4,1
C. 0, 1, 4, 6, 4, 1,0
D. 0,4,6,4,0

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.