Hey there!
k - 10/2 = -7
k - 5 = -7
ADD 5 to BOTH SIDES
k - 5 + 5 = -7 + 5
CANCEL out: -5 + 5 because that gives you 0
KEEP: -7 + 5 because it helps solve for the k-value
NEW EQUATION: k = -5 + 7
SIMPLIFY IT & YOU HAVE YOUR ANSWER!
k = -2
Therefore, your answer is: k = -2
Good luck on your assignment and enjoy your day!
~Amphitrite1040:)