The axis of symmety is the x value of the vertex
to find the x value of the vertex of ax^2+bx+c=0
x value=-b/2a
3x^2+bx+4=0
3/2=vertex
-b/2(3)=3/2
-b/6=3/2
times 6
-b=18/2
-b=9
times -1
b=-9
You start with the top number of each fraction and multiply them. So 2x3=6. Next you take the bottom number and multiply. So 3x4=12. That would give you a fraction of 6/12. 6 is half of 12 so 6/12 simplified is equal to 1/2. Hope this helps!