((n+3)!)/((n+1)!)=30

解答

\frac{( n + 3 ) !}{( n + 1 ) !} = 30

n = 3, n = - 8

求解步骤

\frac{( n + 3 ) !}{( n + 1 ) !} = 30

化简

\frac{( n + 3 ) !}{( n + 1 ) !} : (n + 3) (n + 2)

(n + 3) (n + 2) = 30

解

(n + 3) (n + 2) = 30 : n = 3, n = - 8

n = 3, n = - 8

g = \frac{9.8 m}{s ^{2}}

\frac{0.2 x + 5}{3.5 x - 3} = \frac{2}{5}

\frac{( 19 - x )}{( 42 - x )} = 0.12

so l v e f or x, z = y^{2} + 2 f (\frac{1}{x} + lo g_{10} (y))

so l v e f or a, (p + 4) - 2 \frac{p}{a} = 8