Simplify Expressions
1. Problem 39: Simplify the expression \[\frac{4 - \frac{9}{x^2}}{2 - \frac{3}{x}}\].
Step 1: Find a common denominator in numerator and denominator separately.
Numerator: $$4 - \frac{9}{x^2} = \frac{4x^2 - 9}{x^2}$$
Denominator: $$2 - \frac{3}{x} = \frac{2x - 3}{x}$$
Step 2: Rewrite the whole fraction:
$$\frac{\frac{4x^2 - 9}{x^2}}{\frac{2x - 3}{x}} = \frac{4x^2 - 9}{x^2} \times \frac{x}{2x - 3} = \frac{4x^2 - 9}{x^2} \times \frac{x}{2x - 3}$$
Step 3: Simplify the multiplication:
$$\frac{4x^2 - 9}{x^2} \times \frac{x}{2x - 3} = \frac{(4x^2 - 9) x}{x^2 (2x - 3)} = \frac{(4x^2 - 9)}{x (2x - 3)}$$
Step 4: Factor numerator:
$$4x^2 - 9 = (2x - 3)(2x + 3)$$
So
$$\frac{(2x - 3)(2x + 3)}{x (2x - 3)}$$
Step 5: Cancel common factor \(2x - 3\):
$$\frac{2x + 3}{x} = 2 + \frac{3}{x}$$
Answer to 39: (a) \(2 + \frac{3}{x}\)
2. Problem 40: Simplify \[\frac{\frac{1}{x} - \frac{1}{y}}{x - y}\].
Step 1: Combine numerator:
$$\frac{1}{x} - \frac{1}{y} = \frac{y - x}{xy}$$
Step 2: Write entire fraction:
$$\frac{\frac{y - x}{xy}}{x - y} = \frac{y - x}{xy} \times \frac{1}{x - y}$$
Note \(y - x = -(x - y)\), so:
$$= \frac{-(x - y)}{xy} \times \frac{1}{x - y} = -\frac{1}{xy}$$
Answer to 40: (a) \(-\frac{1}{xy}\)
3. Problem 41: Simplify \[\frac{\frac{x}{y} - \frac{y}{x}}{\frac{1}{y} - \frac{1}{x}}\].
Step 1: Simplify numerator:
$$\frac{x}{y} - \frac{y}{x} = \frac{x^2 - y^2}{xy} = \frac{(x - y)(x + y)}{xy}$$
Step 2: Simplify denominator:
$$\frac{1}{y} - \frac{1}{x} = \frac{x - y}{xy}$$
Step 3: Entire fraction:
$$\frac{\frac{(x - y)(x + y)}{xy}}{\frac{x - y}{xy}} = \frac{(x - y)(x + y)}{xy} \times \frac{xy}{x - y}$$
Simplify:
$$= x + y$$
Answer to 41: (b) \(x + y\)
4. Problem 42: Simplify \[\frac{\frac{x^2 - y^2}{xy}}{\frac{3}{x} - \frac{3}{y}}\].
Step 1: Numerator:
$$\frac{x^2 - y^2}{xy} = \frac{(x - y)(x + y)}{xy}$$
Step 2: Denominator:
$$\frac{3}{x} - \frac{3}{y} = 3\left(\frac{1}{x} - \frac{1}{y}\right) = 3 \frac{y - x}{xy} = \frac{3(y - x)}{xy}$$
Step 3: Entire fraction:
$$\frac{\frac{(x - y)(x + y)}{xy}}{\frac{3(y - x)}{xy}} = \frac{(x - y)(x + y)}{xy} \times \frac{xy}{3(y - x)}$$
Recall \(y - x = -(x - y)\), so denominator term is \(3 (y - x) = -3(x - y)\):
$$= \frac{(x - y)(x + y)}{xy} \times \frac{xy}{-3(x - y)} = -\frac{(x + y)}{3}$$
Since answer choices do not have negative sign explicitly and only (c) matches magnitude,
Answer is: (d) none
5. Problem 43: Simplify $$\sqrt[3]{9x^5y^2} \times \sqrt[3]{9z^5} = \sqrt[3]{9 \times 9 \times x^5 \times y^2 \times z^5} = \sqrt[3]{81 x^5 y^2 z^5}$$
Factor 81 as $$3^4$$:
$$= \sqrt[3]{3^4 x^5 y^2 z^5} = 3^{4/3} x^{5/3} y^{2/3} z^{5/3}$$
Rewrite:
$$= 3 \times 3^{1/3} \times x^{1 + 2/3} \times y^{2/3} \times z^{1 + 2/3} = 3 x^{2} z \times \sqrt[3]{3 x^{2} y^{2} z^{2}}$$
Answer to 43: (c) \(3 x^{2} z \times \sqrt[3]{3 x^{2} y^{2} z^{2}}\)
6. Problem 44: Simplify \(\sqrt[4]{32 x^{15} y^{11}}\)
Step 1: Express 32 as \(2^5\).
Step 2: Distribute root:
$$ = \sqrt[4]{2^5} \times \sqrt[4]{x^{15}} \times \sqrt[4]{y^{11}} = 2^{5/4} x^{15/4} y^{11/4}$$
Step 3: Break powers into integer and fractional parts:
$$2^{5/4} = 2^{1} \times 2^{1/4} = 2 \times \sqrt[4]{2}$$
$$x^{15/4} = x^{3 + 3/4} = x^{3} \times x^{3/4}$$
$$y^{11/4} = y^{2 + 3/4} = y^{2} \times y^{3/4}$$
Step 4: Combine:
$$= 2 x^{3} y^{2} \times \sqrt[4]{2 x^{3} y^{3}}$$
Answer to 44: (c) \(2 x^{3} y^{2} \times \sqrt[4]{2 x^{3} y^{3}}\)
7. Problem 45: Simplify $$\frac{27 x^{3} y^{2}}{\sqrt{9 x y}}$$
Step 1: Simplify the denominator:
$$\sqrt{9 x y} = 3 \sqrt{x y}$$
Step 2: Rewrite expression:
$$\frac{27 x^{3} y^{2}}{3 \sqrt{x y}} = 9 x^{3} y^{2} \times \frac{1}{\sqrt{x y}}$$
Step 3: Express radical as fractional power:
$$= 9 x^{3} y^{2} \times (x y)^{-\frac{1}{2}} = 9 x^{3 - \frac{1}{2}} y^{2 - \frac{1}{2}} = 9 x^{\frac{5}{2}} y^{\frac{3}{2}}$$
Step 4: Write answer with radical:
$$9 x^{\frac{5}{2}} y^{\frac{3}{2}} = 9 x^{2} y \times x^{\frac{1}{2}} y^{\frac{1}{2}} = 9 x^{2} y \times \sqrt{x y}$$
Answer to 45: (b) \(9 x^{2} y \times \sqrt{x y}\)
8. Problem 46: Simplify $$\frac{\sqrt[3]{x^{4} y^{5}}}{\sqrt[3]{x y^{2}}} = \sqrt[3]{\frac{x^{4} y^{5}}{x y^{2}}} = \sqrt[3]{x^{3} y^{3}}$$
Simplify inside cube root:
$$= \sqrt[3]{(x y)^{3}} = x y$$
Answer to 46: (a) \(x y\)
9. Problem 47: Simplify $$\sqrt[3]{256 x^{5}} - \sqrt[3]{4 x^{5}}$$
Step 1: Express 256 and 4 as powers:
$$256 = 2^{8}, 4 = 2^{2}$$
Step 2: Write cube roots:
$$\sqrt[3]{2^{8} x^{5}} - \sqrt[3]{2^{2} x^{5}} = 2^{8/3} x^{5/3} - 2^{2/3} x^{5/3} = x^{5/3} (2^{8/3} - 2^{2/3})$$
Step 3: Factor out \(2^{2/3}\):
$$= x^{5/3} 2^{2/3} (2^{6/3} - 1) = x^{5/3} 2^{2/3} (2^{2} - 1) = x^{5/3} 2^{2/3} (4 - 1) = 3 x^{5/3} 2^{2/3}$$
Step 4: Simplify:
$$= 3 x^{5/3} \times \sqrt[3]{4}$$
Answer: \(3 x^{\frac{5}{3}} \times \sqrt[3]{4}\) (no options given to select)
Final summary:
"39": (a), "40": (a), "41": (b), "42": (d), "43": (c), "44": (c), "45": (b), "46": (a), "47": answered with simplified form