x/7+(21)/(x+5)= 47/7

解答

\frac{x}{7} + \frac{21}{x + 5} = \frac{47}{7}

x = 44, x = - 2

求解步骤

\frac{x}{7} + \frac{21}{x + 5} = \frac{47}{7}

乘以最小公倍数

x (x + 5) + 147 = 47 (x + 5)

解

x (x + 5) + 147 = 47 (x + 5) : x = 44, x = - 2

x = 44, x = - 2

验证解

找到无定义的点（奇点）:

x = - 5

将不在定义域的点与解相综合:

x = 44, x = - 2

\frac{x + 1}{x + 3} = \frac{2}{x}

\frac{5}{x} - \frac{1}{2 x} = \frac{9}{x ^{2}}

\frac{1}{x + 2} - \frac{1}{x + 3} = \frac{1}{2}

\frac{4}{( 2 x + 3 )} = \frac{3}{( x - 3 )}

\frac{3}{x + 1} + \frac{1}{x - 1} = 2