Solve for $u$. \[ \begin{array}{l} -3+2 u+6=-8 u-7 \\ u= \end{array} \]

Step 1 ：The given equation is a linear equation in one variable, $u$. To solve for $u$, we need to isolate $u$ on one side of the equation. We can do this by combining like terms and then using the properties of equality to solve for $u$.

Step 2 ：Combine like terms on both sides of the equation: \(-3 + 2u + 6 = -8u - 7\) simplifies to \(10u = -6\).

Step 3 ：Divide both sides of the equation by 10 to solve for $u$: \(u = -6/10\).

Step 4 ：Simplify the right side of the equation to get the final answer: \(u = \boxed{-1}\).