1. **State the problem:** Simplify and express with positive exponents the following expressions:
a) $$\left( \frac{a^{-2}}{b^{-5}} \right)^{-3}$$
b) $$\left( \frac{32a^{2}b^{-4}}{4a^{-8}b^{-2}} \right) \left( \frac{-8a^{-2}}{-3b^{-3}} \right)$$
c) $$\left( \frac{12x^{3}y^{-1}}{-8x^{-1}y^{5}} \right)^{-2}$$
2. **Recall exponent rules:**
- $$\left( \frac{x^{m}}{y^{n}} \right)^{p} = \frac{x^{mp}}{y^{np}}$$
- $$x^{a} \cdot x^{b} = x^{a+b}$$
- $$\frac{x^{a}}{x^{b}} = x^{a-b}$$
- Negative exponents: $$x^{-m} = \frac{1}{x^{m}}$$
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### a) Simplify $$\left( \frac{a^{-2}}{b^{-5}} \right)^{-3}$$
3. Apply the power of a quotient rule:
$$\left( \frac{a^{-2}}{b^{-5}} \right)^{-3} = \frac{a^{-2 \times (-3)}}{b^{-5 \times (-3)}} = \frac{a^{6}}{b^{15}}$$
4. The expression is already with positive exponents.
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### b) Simplify $$\left( \frac{32a^{2}b^{-4}}{4a^{-8}b^{-2}} \right) \left( \frac{-8a^{-2}}{-3b^{-3}} \right)$$
5. Simplify the first fraction:
$$\frac{32a^{2}b^{-4}}{4a^{-8}b^{-2}} = \frac{32}{4} \cdot \frac{a^{2}}{a^{-8}} \cdot \frac{b^{-4}}{b^{-2}} = 8 \cdot a^{2 - (-8)} \cdot b^{-4 - (-2)} = 8a^{10}b^{-2}$$
6. Simplify the second fraction:
$$\frac{-8a^{-2}}{-3b^{-3}} = \frac{-8}{-3} \cdot a^{-2} \cdot b^{3} = \frac{8}{3} a^{-2} b^{3}$$
7. Multiply the two results:
$$8a^{10}b^{-2} \times \frac{8}{3} a^{-2} b^{3} = \frac{64}{3} a^{10 + (-2)} b^{-2 + 3} = \frac{64}{3} a^{8} b^{1} = \frac{64}{3} a^{8} b$$
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### c) Simplify $$\left( \frac{12x^{3}y^{-1}}{-8x^{-1}y^{5}} \right)^{-2}$$
8. Simplify inside the parentheses first:
$$\frac{12x^{3}y^{-1}}{-8x^{-1}y^{5}} = \frac{12}{-8} \cdot x^{3 - (-1)} \cdot y^{-1 - 5} = -\frac{3}{2} x^{4} y^{-6}$$
9. Now raise to the power $$-2$$:
$$\left(-\frac{3}{2} x^{4} y^{-6} \right)^{-2} = \left(-\frac{3}{2}\right)^{-2} x^{4 \times (-2)} y^{-6 \times (-2)} = \left(-\frac{3}{2}\right)^{-2} x^{-8} y^{12}$$
10. Simplify the coefficient:
$$\left(-\frac{3}{2}\right)^{-2} = \left(-\frac{2}{3}\right)^{2} = \frac{4}{9}$$
11. So the expression is:
$$\frac{4}{9} x^{-8} y^{12}$$
12. Express with positive exponents:
$$\frac{4 y^{12}}{9 x^{8}}$$
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**Final answers:**
- a) $$\frac{a^{6}}{b^{15}}$$
- b) $$\frac{64}{3} a^{8} b$$
- c) $$\frac{4 y^{12}}{9 x^{8}}$$
Exponent Simplify D70B63
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