It's already solved for x.  If the left side of an equation 
is " x = " and the letter x does not appear on the right side
at all, then the equation is solved for x. 

Did you mean to say you were solving for t and not x, and
just mistyped?

If so, then to solve for t, then we get zero on one side



Swap sides 



Subtract x from both sides:



Put parentheses around the last two terms on the left
to show that together they can be used to substitute
for c in the quadratic formula.  This step may be
skipped:




Then we use the quadratic formula with , , 







 







Factor 2 out of the top



Cancel the 2 in the top into the 12 on the bottom
getting 6 on the bottom:





That's really two solutions:

1.  

2.  

Edwin