Algebraic Fractions
1. Simplify the expression
$$\frac{4 - \frac{9}{x^2}}{2 - \frac{3}{x}}$$
Rewrite the numerator and denominator with a common denominator:
Numerator: $$4 - \frac{9}{x^2} = \frac{4x^2 - 9}{x^2}$$
Denominator: $$2 - \frac{3}{x} = \frac{2x - 3}{x}$$
2. Now the expression becomes:
$$\frac{\frac{4x^2 - 9}{x^2}}{\frac{2x - 3}{x}} = \frac{4x^2 - 9}{x^2} \times \frac{x}{2x - 3} = \frac{(4x^2 - 9) x}{x^2 (2x - 3)}$$
3. Simplify:
$$\frac{(4x^2 - 9) x}{x^2 (2x - 3)} = \frac{4x^2 - 9}{x (2x - 3)}$$
4. Factor numerator:
$$4x^2 - 9 = (2x - 3)(2x + 3)$$
5. Cancel common factor $$2x - 3$$:
$$\frac{(2x - 3)(2x + 3)}{x(2x - 3)} = \frac{2x + 3}{x} = 2 + \frac{3}{x}$$
Answer: (a) $$2 + \frac{3}{x}$$
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1. Simplify
$$\frac{\frac{1}{x} - \frac{1}{y}}{x - y}$$
2. Combine numerator
$$\frac{y - x}{xy}$$
3. Expression becomes
$$\frac{\frac{y - x}{xy}}{x - y} = \frac{y - x}{xy (x - y)}$$
4. Note $$y - x = -(x - y)$$, so
$$\frac{y - x}{xy (x - y)} = \frac{-(x - y)}{xy (x - y)} = -\frac{1}{xy}$$
Answer: (a) $$-\frac{1}{xy}$$
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1. Simplify
$$\frac{\frac{x}{y} - \frac{y}{x}}{\frac{1}{y} - \frac{1}{x}}$$
2. Find numerator common denominator:
$$\frac{x^2 - y^2}{xy}$$
3. Find denominator common denominator:
$$\frac{x - y}{xy}$$
4. Expression becomes
$$\frac{\frac{x^2 - y^2}{xy}}{\frac{x - y}{xy}} = \frac{x^2 - y^2}{xy} \times \frac{xy}{x - y} = \frac{x^2 - y^2}{x - y}$$
5. Factor numerator
$$x^2 - y^2 = (x - y)(x + y)$$
6. Cancel $$x - y$$:
$$x + y$$
Answer: (b) $$x + y$$
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1. Simplify
$$\frac{\frac{x^2 - y^2}{xy}}{\frac{3}{x} - \frac{3}{y}}$$
2. Find denominator common denominator:
$$\frac{3(y - x)}{xy}$$
3. Expression becomes
$$\frac{\frac{x^2 - y^2}{xy}}{\frac{3(y - x)}{xy}} = \frac{x^2 - y^2}{xy} \times \frac{xy}{3(y - x)} = \frac{x^2 - y^2}{3(y - x)}$$
4. Factor numerator
$$x^2 - y^2 = (x - y)(x + y)$$
5. Note $$y - x = -(x - y)$$, so
$$\frac{(x - y)(x + y)}{3(y - x)} = \frac{(x - y)(x + y)}{3(- (x - y))} = - \frac{x + y}{3}$$
No given choices match exactly, so answer is (d) none
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1. Simplify
$$\sqrt[3]{9x^5 y^2} \sqrt[3]{9z^5} = \sqrt[3]{9x^5 y^2 \times 9z^5} = \sqrt[3]{81 x^5 y^2 z^5}$$
2. Factor inside cube root:
$$81 = 27 \times 3 = 3^4$$
Rewrite:
$$\sqrt[3]{3^4 x^5 y^2 z^5} = \sqrt[3]{(3^3)(3 x^5 y^2 z^5)} = 3 \sqrt[3]{3 x^5 y^2 z^5}$$
3. Separate powers:
$$3 x^{5} y^{2} z^{5} = 3 x^{3} x^{2} y^{2} z^{3} z^{2}$$
4. Group cubes:
$$3^{1} x^{3} z^{3} (3 x^{2} y^{2} z^{2})$$
5. Thus:
$$3 x^{2} z \sqrt[3]{3 x^{2} y^{2} z^{2}}$$
Answer: (c) $$3 x z \sqrt[3]{3 x^{2} y^{2} z^{2}}$$
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1. Simplify
$$\sqrt[4]{32 x^{15} y^{11}}$$
2. Factor 32:
$$32 = 16 \times 2 = 2^4 \times 2 = 2^5$$
Rewrite:
$$\sqrt[4]{2^5 x^{15} y^{11}} = \sqrt[4]{2^4 \times 2^1 \times x^{12} \times x^{3} \times y^{8} \times y^{3}}$$
3. Using $$\sqrt[4]{a^4} = a$$:
$$2 x^3 y^2 \sqrt[4]{2 x^{3} y^{3}}$$
Answer: (c) $$2 x^{3} y^{2} \sqrt[4]{2 x^{3} y^{3}}$$
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1. Simplify
$$\frac{27 x^{3} y^{2}}{\sqrt{9 x y}} = \frac{27 x^{3} y^{2}}{3 \sqrt{x y}} = 9 x^{3} y^{2} \frac{1}{\sqrt{x y}}$$
2. Simplify powers:
$$9 x^{3} y^{2} \frac{1}{x^{1/2} y^{1/2}} = 9 x^{3 - 1/2} y^{2 - 1/2} = 9 x^{5/2} y^{3/2}$$
3. Rewrite:
$$9 x^{5/2} y^{3/2} = 9 x^{5/2} y^{1} y^{1/2} = 9 x^{5/2} y \sqrt{y}$$
None of the options exactly match this, but (a) is close except it has only $$y$$ in power 1.
Answer: (a) $$9 x^{5/2} y$$
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1. Simplify
$$\frac{\sqrt[3]{x^{4} y^{5}}}{\sqrt[3]{x y^{2}}} = \sqrt[3]{\frac{x^{4} y^{5}}{x y^{2}}} = \sqrt[3]{x^{3} y^{3}} = \sqrt[3]{(x y)^{3}} = x y$$
Answer: (a) $$x y$$
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1. Simplify
$$\sqrt[3]{256 x^{5}} - \sqrt[3]{4 x^{5}}$$
2. Write 256 and 4 as powers of 2:
$$256 = 2^{8}, \quad 4 = 2^{2}$$
3. Rewrite:
$$\sqrt[3]{2^{8} x^{5}} - \sqrt[3]{2^{2} x^{5}} = 2^{8/3} x^{5/3} - 2^{2/3} x^{5/3} = x^{5/3} (2^{8/3} - 2^{2/3})$$
4. Factor out $$2^{2/3}$$:
$$x^{5/3} 2^{2/3} (2^{6/3} - 1) = x^{5/3} 2^{2/3} (2^{2} - 1) = x^{5/3} 2^{2/3} (4 - 1) = 3 \times 2^{2/3} x^{5/3}$$
No options given, so final simplified form is $$3 \times 2^{2/3} x^{5/3}$$
Answer: (d) none