EDGE Math 8

Perform the indicated operations and simplify the resulting expression. Choose the correct answer.

1.	$\frac{3 x}{5 x} - \frac{5 x + 6}{15 x^{4}}$

\frac{9 x^{4} - 5 x - 6}{15 x^{4}}

\frac{9 x^{4} - 5 x + 6}{15 x^{4}}

\frac{9 x^{3} - 5 x + 6}{15 x^{4}}

none of the choices

Answer: $\frac{9 x^{4} - 5 x - 6}{15 x^{4}}$

2.	$\frac{x - 5}{12 x^{3}} - \frac{2 x - 2}{28 x^{5}}$

\frac{7 x^{3} - 35 x^{2} - 2 x + 6}{84 x^{5}}

\frac{7 x^{3} - 35 x^{2} - 6 x + 6}{84 x^{5}}

\frac{7 x^{3} - 35 x^{2} - 6 x + 2}{84 x^{5}}

none of the choices

Answer: $\frac{7 x^{3} - 35 x^{2} - 6 x + 6}{84 x^{5}}$

3.	$\frac{a + b}{3 a^{2} b} + \frac{a - 2 b}{6 a b^{2}}$

\frac{2 b^{2} + 4 a b + a^{2}}{6 a^{2} b^{2}}

\frac{2 b^{2} + a^{2}}{6 a^{2} b^{2}}

\frac{2 b^{2} - 4 a b + a^{2}}{6 a^{2} b^{2}}

none of the choices

Answer: $\frac{2 b^{2} + a^{2}}{6 a^{2} b^{2}}$

4.	$\frac{3 a + 2 b}{4 a b} - \frac{2 a + 5 b}{9 a b^{3}}$

\frac{27 a b^{2} + 2 b^{3} - 8 a + 20 b}{36 a b^{3}}

\frac{27 a b^{2} + 2 b^{3} - 8 a + 5 b}{36 a b^{3}}

\frac{27 a b^{2} + 18 b^{3} - 8 a - 20 b}{36 a b^{3}}

none of the choices

Answer: $\frac{27 a b^{2} + 18 b^{3} - 8 a - 20 b}{36 a b^{3}}$

5.	$\frac{x + 4}{x + 1} + \frac{2}{x}$

\frac{x + 2}{x}

\frac{x^{2} + 6 x + 2}{x (x + 1)}

\frac{x^{2} + 4 x + 2}{x (x + 1)}

none of the choices

Answer: $\frac{x^{2} + 6 x + 2}{x (x + 1)}$

6.	$\frac{y - 4}{y} + \frac{6}{y - 2}$

\frac{y^{2} + 8}{y (y - 2)}

\frac{y^{2} - 2 y + 4}{y}

\frac{y^{2} - 12 y + 8}{y (y - 2)}

none of the choices

Answer: $\frac{y^{2} + 8}{y (y - 2)}$

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