38. (-$$\frac{3}{5}$$k)³ ⋅ (-$$\frac{5}{3}$$k²)².

38. (-$$\frac{3}{5}$$k)³ ⋅ (-$$\frac{5}{3}$$k²)² = (-$$\frac{3}{5}$$)³ ⋅ k³ ⋅ (-$$\frac{5}{3}$$)² ⋅ (k²)² = -$$\frac{27}{125}$$ ⋅ k³ ⋅ $$\frac{25}{9}$$ ⋅ k⁴ = -$$\frac{27}{125}$$ ⋅ $$\frac{25}{9}$$ ⋅ k³ ⋅ k⁴ = -$$\frac{3}{5}$$k⁷

Ответ: -$$\frac{3}{5}$$k⁷