Question

a+6b=18 4a-3b=0

Answer 1

Do you need to find both A and B?

Answer 2

Yes

Answer 3

You need to look at your variables and decide which one you can change so that when you add the equations (one above the other) you cancel out a variable. I am going to call the first equation 1 and the second equation 2.
\[a+6b=18\]
\[4a-3b=0\]
Do you want to cancel out a or b? To cancel out a you would multiply equation 1 by -4. To cancel out b you would multiply equation 2 by 2. Which one do you think is easier? I am going to cancel out b.
\[(4a-3b=0) \times 2 = 8a-6b=0\]
Now your problem reads like this:
\[a+6b=18\]
\[8a-6b=0\]
Now you add the two equations together to get...
\[a+6b=18\]+
\[8a-6b=0\]--------
\[9a+0b=0\] or \[9a=0\] or \[a=0\]

Now plug in your a value into either equation to get your b value!

Your instructions may ask you to solve this in a specific way, I may not be helping.