Question 13366
Here what I've tried so far. 
2 [k-3(4-2k)] = 2(k-3) + 3


Your mistake is in the next step!  You must multiply -3 times the 4 and times the -2k.
2[k-3-4+2k]=2k-6+3  Error in this step!


It should be this:
2[k-12 + 6k]= 2k - 6 + 3
2k - 24 + 12k = 2k - 3
14k - 24 = 2k - 3


Subtract 2k from each side:
14k - 2k - 24 = 2k - 2k - 3
12k - 24 = -3


Add 24 to each side:
12k - 24 + 24 = -3 + 24
12k = 21

{{{k = 21/12 = 7/4 }}}


R^2 at SCC