Question

what is the dimensions if the poster is enlarged by a factor of 7over 2 the numbers are 6 inches and 18 inches

Answer 1

if you mean a factor of (7/2) or 3.5 then the new measurment is

as 6*7= 42 
42/2 = 21

18*7=126
126/2=63

21 inches by 63 inches