Question

Помогите пожалуйста, очень надо)
С 7.6.40
До 7.6.46

Answer 1

7,40 \ \.....=(x+1)* frac{x-1}{(x+1)(x+1)}= frac{x-1}{x+1} \ x=4 \ frac{4-1}{4+1}= frac{3}{5} =0.6 \ \ 7.41 \ .....= frac{7+5}{35a}* frac{a^{2} }{8}= frac{3a}{70} \ a= -4,2 \ -frac{3*4.2}{70}=-12,6:70=-0.18 \ \ 7.42 \ .......= frac{9}{20a} frac{a^{2} }{9}= frac{a}{20} \ a=7.8 \ frac{7.8}{20} =0.39 \ \ 7.43 \ .....= frac{b^{2}-49a^{2} }{7ab}* frac{1}{b+7a}= frac{(b+7a)(b-7a)}{7ab}* frac{1}{b+7a}= frac{b-7a}{7ab} \ a= frac{1}{7} , b= frac{1}{6} \ [/tex]$frac{ frac{1}{6}-7* frac{1}{7} }{7* frac{1}{7}* frac{1}{6} } = frac{ frac{1}{6}-1 }{ frac{1}{6} } =- frac{ frac{5}{6} }{ frac{1}{6} } =-5 \ \ 7.44 \ .....= frac{4b^{2} -25 a^{2} }{10ab}* frac{1}{2b+5a}= frac{(2b+5a)(2b-5a)}{10ab}*  frac{1}{2b+5a}= frac{2b-5a}{10ab} \ a= frac{1}{5}, b= frac{1}{9} \ frac{2* frac{1}{9}-5* frac{1}{5} }{10* frac{1}{5} * frac{1}{9} } = frac{ frac{2}{9}-1 }{ frac{2}{9} } =- frac{7}{9} * frac{9}{2} =- frac{7}{2}=-3.5 \ \ 7.45$$[tex] ......=frac{ y^{2} -4 x^{2} }{2xy} * frac{1}{y+2x} = frac{(y-2x)(y+2x)}{2xy(y+2x)}= frac{y-2x}{2xy} \ x= frac{1}{7} , y= frac{1}{8} \ frac{ frac{1}{8}-2* frac{1}{7} }{2* frac{1}{7} *frac{1}{8} } = frac{ frac{7}{56}- frac{16}{56} }{ frac{1}{28} } =- frac{9}{56}* 28=-4.5$
$\ 7.46 \ .......= frac{9y^{2} - 4x^{2} }{6xy} * frac{1}{3y+2x} = frac{(3y+2x)(3y-2x)}{6xy(3y+2x)}= frac{3y-2x}{6xy} \ x= frac{1}{8} , y= frac{1}{6} \ frac{3* frac{1}{6}-2* frac{1}{8} }{6* frac{1}{8} * frac{1}{6} } = frac{ frac{1}{4} }{ frac{1}{8} } = frac{1}{4} *8=2$