1. Problem: Simplify $$\frac{2}{x+1} + \frac{1}{x-2} - \frac{1}{x^2 - 1}$$.
2. Note that $$x^2 - 1 = (x+1)(x-1)$$.
3. Find common denominator: $$ (x+1)(x-2)(x-1) $$.
4. Rewrite each fraction with the common denominator:
$$\frac{2}{x+1} = \frac{2(x-2)(x-1)}{(x+1)(x-2)(x-1)}$$
$$\frac{1}{x-2} = \frac{1(x+1)(x-1)}{(x+1)(x-2)(x-1)}$$
$$\frac{1}{x^2 -1} = \frac{1(x-2)}{(x+1)(x-2)(x-1)}$$
5. Combine numerators:
$$2(x-2)(x-1) + (x+1)(x-1) - (x-2)$$
6. Expand terms:
$$2(x^2 -3x + 2) + (x^2 -1) - (x - 2)$$
$$= 2x^2 -6x +4 + x^2 -1 - x + 2$$
7. Combine like terms:
$$3x^2 -7x + 5$$
8. So the simplified expression is:
$$\frac{3x^2 - 7x + 5}{(x+1)(x-2)(x-1)} = \frac{3x^2 - 7x + 5}{(x - 2)(x^2 - 1)}$$
Answer: (c)
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1. Problem: Simplify $$\frac{1}{x-3} + \frac{1}{x+3}$$.
2. Common denominator: $$ (x-3)(x+3) = x^2 - 9 $$.
3. Rewrite fractions:
$$\frac{1(x+3)}{x^2-9} + \frac{1(x-3)}{x^2-9} = \frac{x+3+x-3}{x^2-9} = \frac{2x}{x^2-9}$$
Answer: (b)
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1. Problem: Simplify $$-\frac{2}{x} + \frac{1}{x-1} + \frac{1}{x+1}$$.
2. Find common denominator: $$x(x-1)(x+1) = x(x^2 - 1)$$.
3. Rewrite fractions with common denominator:
$$-\frac{2(x-1)(x+1)}{x(x-1)(x+1)} + \frac{1(x)(x+1)}{x(x-1)(x+1)} + \frac{1(x)(x-1)}{x(x-1)(x+1)}$$
4. Expand numerators:
$$-2(x^2 - 1) + x(x+1) + x(x-1) = -2x^2 + 2 + x^2 + x + x^2 - x = 2$$
5. Simplify numerator:
$$ -2x^2 + 2 + x^2 + x + x^2 - x = 2 $$
6. So expression is:
$$\frac{2}{x(x^2 - 1)}$$
Answer: (c)
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1. Problem: Simplify $$\frac{x^2 - 3x + 2}{x^2 + 5x + 4} \times \frac{x + 1}{x - 1}$$.
2. Factor polynomials:
$$x^2 - 3x + 2 = (x - 1)(x - 2)$$
$$x^2 + 5x + 4 = (x + 4)(x + 1)$$
3. Substitute factors:
$$\frac{(x - 1)(x - 2)}{(x + 4)(x + 1)} \times \frac{x + 1}{x - 1}$$
4. Cancel common terms:
$$\frac{(x - 2)}{(x + 4)}$$
Answer: (c)
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1. Problem: Simplify $$\frac{4x^2 - 4}{x^2 + 2x + 1} \cdot \frac{x + 1}{x - 1}$$.
2. Factor:
$$4x^2 - 4 = 4(x^2 - 1) = 4(x-1)(x+1)$$
$$x^2 + 2x + 1 = (x + 1)^2$$
3. Substitute:
$$\frac{4(x-1)(x+1)}{(x + 1)^2} \times \frac{x + 1}{x - 1}$$
4. Cancel terms:
Cancel $$ (x+1) $$ and $$ (x-1) $$ in numerator and denominator:
$$\frac{4(x+1)(x-1)}{(x + 1)^2} \times \frac{x + 1}{x - 1} = 4$$
Answer: (c)
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1. Problem: Simplify $$\frac{x^2 - 9}{x^2 + 6x + 9} \cdot \frac{x + 3}{x - 9}$$.
2. Factor:
$$x^2 - 9 = (x - 3)(x + 3)$$
$$x^2 + 6x + 9 = (x + 3)^2$$
3. Substitute:
$$\frac{(x - 3)(x + 3)}{(x + 3)^2} \times \frac{x + 3}{x - 9}$$
4. Cancel $$ (x + 3) $$:
$$\frac{x - 3}{x + 3} \times \frac{1}{x - 9} (x + 3)$$ , reduces to
$$\frac{x - 3}{x - 9}$$
Answer: (a)
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1. Problem: Simplify $$\frac{3x^2 - 12}{x + 2} \cdot \frac{x}{x - 2}$$.
2. Factor numerator:
$$3x^2 - 12 = 3(x^2 - 4) = 3(x-2)(x+2)$$
3. Substitute:
$$\frac{3(x-2)(x+2)}{x + 2} \cdot \frac{x}{x - 2}$$
4. Cancel $$ (x + 2) $$ and $$ (x - 2) $$:
$$3x$$
Answer: (a)
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1. Problem: Simplify $$\frac{2 - 3x - 2x^2}{x^2 + 3x} \div \frac{x^2 + 3x + 2}{x + 3}$$.
2. Factor denominators and numerators:
Numerator of first fraction: $$2 - 3x - 2x^2 = - (2x^2 + 3x - 2)$$
Factor: $$2x^2 + 3x - 2 = (2x - 1)(x + 2)$$
So numerator is $$- (2x - 1)(x + 2)$$
3. Denominator of first fraction: $$x^2 + 3x = x(x + 3)$$
4. Numerator of second fraction: $$x^2 + 3x + 2 = (x + 1)(x + 2)$$
5. Rewrite division as multiplication by reciprocal:
$$\frac{- (2x - 1)(x + 2)}{x(x + 3)} \times \frac{x + 3}{(x + 1)(x + 2)}$$
6. Cancel $$ (x + 2) $$ and $$ (x + 3) $$:
$$\frac{-(2x - 1)}{x} \times \frac{1}{x + 1} = \frac{-(2x - 1)}{x(x + 1)} = \frac{1 - 2x}{x(x + 1)}$$
Answer: (c)
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1. Problem: Simplify $$\frac{x + 2}{1 + \frac{2}{x}}$$.
2. Simplify denominator:
$$1 + \frac{2}{x} = \frac{x + 2}{x}$$
3. Therefore:
$$\frac{x + 2}{\frac{x + 2}{x}} = (x + 2) \times \frac{x}{x + 2} = x$$
Answer: (a)
Algebra Rational Expressions
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