化简 (3x^2)/(x^2-x-30)-(3x+5)/(x-6)

解答

化简

\frac{3 x ^{2}}{x ^{2} - x - 30} - \frac{3 x + 5}{x - 6}

\frac{- 20 x - 25}{( x + 5 ) ( x - 6 )}

求解步骤

\frac{3 x ^{2}}{x ^{2} - x - 30} - \frac{3 x + 5}{x - 6}

x^{2} - x - 30, x - 6

的最小公倍数:

(x + 5) (x - 6)

根据最小公倍数调整分式

= \frac{3 x ^{2}}{( x + 5 ) ( x - 6 )} - \frac{( 3 x + 5 ) ( x + 5 )}{( x + 5 ) ( x - 6 )}

使用分式法则:

\frac{a}{c} - \frac{b}{c} = \frac{a - b}{c}

= \frac{3 x ^{2} - ( 3 x + 5 ) ( x + 5 )}{( x + 5 ) ( x - 6 )}

化简

3 x^{2} - (3 x + 5) (x + 5) : - 20 x - 25

= \frac{- 20 x - 25}{( x + 5 ) ( x - 6 )}

s im pl i f y \frac{1}{2} lo g_{2} (\frac{1}{2})

e x p an d (2 a - 3 b) (4 a^{2} + 6 ab + 9 b^{2})

f a c t or 2 + 22

e x p an d (x - y) (1 - x y)

s im pl i f y 2 (4 + 15)