展开-(4(9y^2+4x^2))/(81y^3)

解答

展开

- \frac{4 ( 9 y ^{2} + 4 x ^{2} )}{81 y ^{3}}

- \frac{4}{9 y} - \frac{16 x ^{2}}{81 y ^{3}}

求解步骤

- \frac{4 ( 9 y ^{2} + 4 x ^{2} )}{81 y ^{3}}

乘开

4 (9 y^{2} + 4 x^{2}) : 36 y^{2} + 16 x^{2}

= - \frac{36 y ^{2} + 16 x ^{2}}{81 y ^{3}}

使用分式法则:

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

\frac{36 y ^{2} + 16 x ^{2}}{81 y ^{3}} = - (\frac{36 y ^{2}}{81 y ^{3}}) - (\frac{16 x ^{2}}{81 y ^{3}})

= - (\frac{36 y ^{2}}{81 y ^{3}}) - (\frac{16 x ^{2}}{81 y ^{3}})

去除括号:

(a) = a

= - \frac{36 y ^{2}}{81 y ^{3}} - \frac{16 x ^{2}}{81 y ^{3}}

消掉

\frac{36 y ^{2}}{81 y ^{3}} : \frac{4}{9 y}

= - \frac{4}{9 y} - \frac{16 x ^{2}}{81 y ^{3}}

e x p an d \frac{1}{( x - a ) ^{3}} - \frac{1}{( x + a ) ^{2}}

e x p an d \frac{s + 1}{( s ^{2} + 2 s + 10 ) ^{2}}

e x p an d f^{'} (1) (x - 1)

e x p an d \frac{( n + 8 ) ( n + 1 )}{n ( n - 10 )}

e x p an d \frac{2 - pt}{2 ( 2 - p )}