Judging on the questions you have provided I have come to the conclusion that to solve all of these you need to find the value of x by isolating it all on one side and simplifying.
For question #1 the first step would be to subtract 6 from each side. The outcome should be -x=-6-12, and if simplified -x=-18. Next, you want to divide each side by -1 because x needs to always be positive when finding the solution. Your answer for #1 should be X=18, D.
For question #2 the first step you should take is to subtract 1.33 from each side to isolate x. The outcome should be x=7.82-1.33, and if simplified x=6.49. Thus your answer for #2 should be X=6.49, A.
For question #3 the first step you should take to approaching the equation is to isolate x by adding 15.99 towards each side of the equation. The outcome should be x=58.06+15.99, and if simplified x=74.05. Thus your answer for question #3 should be X=74.05, D.
Lastly, for question #4 the first step you should take towards isolating x is to divide the entire equation by 1.32. Your outcome should be x= 6.8 Thus, your answer for the last question, #4, should be X=6.8, C.
