3) $\frac{24 a^{4} b^{3}}{-12 a^{2} b^{3}}$
\(\boxed{-2a^2}\)
Step 1 :Divide the coefficients: \(\frac{24}{-12} = -2\)
Step 2 :Subtract the exponents of a: \(a^{4-2} = a^2\)
Step 3 :Subtract the exponents of b: \(b^{3-3} = b^0 = 1\)
Step 4 :Combine the results: \(-2a^2 * 1 = -2a^2\)
Step 5 :\(\boxed{-2a^2}\)