5) -12 = 3 - 2k - 3k

Explanation:

Step1: Combine like - terms

Combine the terms with $k$ on the right - hand side: $-12 = 3-(2k + 3k)=3 - 5k$.

Step2: Isolate the term with $k$

Subtract 3 from both sides of the equation: $-12-3=-5k$, so $-15 = - 5k$.

Step3: Solve for $k$

Divide both sides by - 5: $k=\frac{-15}{-5}=3$.

Answer:

$k = 3$