Step 1 :\(16x - 6y = -32\) and \(15x + 6y = -123\) are multiplied by 2 and 3 respectively to make the coefficients of y the same, resulting in \(16x - 6y = -32\) and \(15x + 6y = -123\).
Step 2 :The two equations are added to eliminate y: \((16x - 6y) + (15x + 6y) = -32 + (-123)\) simplifies to \(31x = -155\), which further simplifies to \(x = -5\).
Step 3 :The value of x is substituted into the first equation to solve for y: \(8(-5) - 3y = -16\) simplifies to \(-40 - 3y = -16\), which further simplifies to \(y = 8\).
Step 4 :8x is computed using the value of x: \(8x = 8(-5) = -40\).
Step 5 :Final Answer: \(\boxed{-40}\)