Пожалуйста,кто сможет,помогите!!!до 440,поподробнее,заранее спасибо большое:))

436, [latex] \frac{ a^{2}-9}{2a^{2} }* \frac{a}{2a+6}= \frac{(a-3)(a+3)}{2a^{2}} * \frac{a}{2(a+3)} = \frac{a-3}{4a} [/latex] при а=1/27 (1/27-3)/4*1/27 = - 80/27*27/4= - 20 437. [latex]( \frac{4y}{5x} - \frac{5x}{4y}) : (4y+5x)=( \frac{16x^{2}-25 x^{2}}{20xy})* \frac{1}{4y+5x}= \frac{(4y-5x)(4y+5x)}{20xy}* \frac{1}{4y+5x}= [/latex][latex] \frac{4y-5x}{20xy} [/latex] при х=1/5, у=1/8 [latex] \frac{4* \frac{1}{8}-5* \frac{1}{5} }{20* \frac{1}{8}* \frac{1}{5}} = \frac{ \frac{1}{2}-1}{ \frac{1}{2} } = - \frac{1}{2} *2= -1[/latex] 438, [latex]( \frac{2y}{x} - \frac{x}{2y}):(2y+x)= \frac{4y^{2}- x^{2}}{2xy}* \frac{1}{2y+x}= \frac{2y-x}{2xy} [/latex] при х=1/6, у=1/9 [latex] \frac{2* \frac{1}{9} - \frac{1}{6} }{2* \frac{1}{6}* \frac{1}{9}}= \frac{ \frac{4}{18}- \frac{3}{18}}{ \frac{1}{27}} = \frac{1}{18} * 27= \frac{3}{2}=1 \frac{1}{2} [/latex] 439, [latex]( \frac{y}{4x}- \frac{4x}{y} :(y+4x)= \frac{ y^{2}-16 x^{2} }{4xy} * \frac{1}{y+4x} = \frac{y-4x}{4xy} [/latex] при х=1/8, у=1/4 [latex] \frac{ \frac{1}{4}- \frac{4}{8} }{4* \frac{1}{8}* \frac{1}{4}} = - \frac{2}{8} * 8= - 2[/latex] 440, [latex]( \frac{2y}{3x} - \frac{3x}{2y} :(2y+3x)= \frac{4y^{2}-9 x^{2} }{6xy} * \frac{1}{2y+3x} = \frac{2y-3x}{6xy} [/latex] при х=1/3, у=1/4 [latex] \frac{2* \frac{1}{4}-3* \frac{1}{3}}{6* \frac{1}{3}* \frac{1}{4}} = - \frac{1}{2}*2= - 1 [/latex]