For two lines to be proven as parallel they must have the same gradient. The second equation needs to therefore be rearranged into y = mx + c format to see if this is the case.3y-9x+5 = 0 (subtract the 5)3y -9x = - 5 (add the 9x)3y = 9x - 5 (divide by 3)y = 3x - 5/3Gradient of L1 and L2 are the same (3) and are therefore parallel