$\frac{4}{7}=-\frac{8}{x}$
\(\boxed{x = -14}\)
Step 1 :\(\frac{4}{7}=-\frac{8}{x}\)
Step 2 :Cross-multiply: \(4x = -8 \times 7\)
Step 3 :\(4x = -56\)
Step 4 :Divide by 4: \(x = \frac{-56}{4}\)
Step 5 :\(\boxed{x = -14}\)