Final answer:
Without additional context or information for line 'b', it is impossible to determine the value of 'x' for lines 'a' and 'b' to be parallel.
Step-by-step explanation:
To determine the value of 'x' for lines 'a' and 'b' to be parallel, we must recognize that parallel lines have equal slopes. The provided equations do not contain enough context or a standard y=mx+b format to directly compare slopes. However, in an algebraic sense, if lines 'a' and 'b' are to have the same linear coefficient in front of 'x', then the coefficient 'x' already has for line 'a' 3 needs to be the same as that for line 'b', which is not given here. Without additional information regarding line 'b' or the context of the equations provided, it is not possible to accurately determine the value of 'x' for the lines to be parallel. Therefore, this question cannot be answered with the given information.