You can put this solution on YOUR website! First distribute to get rid of your parenthesis:
2(k+3) becomes 2k+6 and -(3k+4) becomes -3k-4 so the equation becomes
now collect like terms:
2k-3k becomes -1k or -k and 6-4 becomes 2, so the equation becomes
now use inverse operations to get the constant on one side of the equal sign and the variable on the other:
2-k+k-k+6+k becomes 2=2k+6
2-6=2k+6-6 becomes -4=2k
-4/2=2k/2 becomes -2=k which gives your solution
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