a) $$(x^{-3})^4 \cdot x^{14} = x^{-3 \cdot 4} \cdot x^{14} = x^{-12} \cdot x^{14} = x^{-12 + 14} = x^2$$
б) $$1,5a^2b^{-3} \cdot 4a^{-3}b^4 = (1,5 \cdot 4)(a^2 \cdot a^{-3})(b^{-3} \cdot b^4) = 6a^{2 - 3}b^{-3 + 4} = 6a^{-1}b^1 = \frac{6b}{a}$$
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