化简 (x^2-2x-15)/(5-x)

解答

化简

\frac{x ^{2} - 2 x - 15}{5 - x}

- x - 3

求解步骤

\frac{x ^{2} - 2 x - 15}{5 - x}

因式分解

x^{2} - 2 x - 15 : (x + 3) (x - 5)

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

5 - x = - (x - 5)

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

约分:

x - 5

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

使用分式法则:

\frac{a}{- 1} = - a

= - (x + 3)

化简

- (x + 3) : - x - 3

= - x - 3

s im pl i f y (3 x^{\frac{1}{2}} y^{2})^{4}

4 \frac{1}{19} - 3 \frac{27}{38}

f a c t or a x^{2} - 3 a^{2} x + 2 a^{3}

s im pl i f y \frac{1 + 3}{3}

f a c t or 12 x^{2} + 17 x - 40