A) is 5 months
b) is option 1 difference of 40
6b+4=2 has one variable
4+6=10 has no variable
Judging by the question I noticed that I can simplify the equation 3x-x+2=12 by one step.
The outcome of simplification should be 2x+2=12.
Next you must subtract 2 from both sides to isolate the x. The new equation should be 2x = 10.
Lastly you must divide both sides by 2, the answer you should get is x=5, D.