Question

Ничерта не понимаю в этих Иррациональных выражениях

Answer 1

$1)\frac{4}{m}-\frac{2}{5m}=\frac{4*5-2}{5m}=\frac{18}{5m} \\\\m=1,5\Rightarrow \frac{18}{5*1,5}=\frac{18}{7,5}=2,4\\\\2)\frac{8-3n}{m}-\frac{6n^{2}+8n}{mn}=\frac{8n-3n^{2}-6n^{2}-8n}{mn}=-\frac{9n^{2}}{mn}=-\frac{9n}{m}\\\\m=10;n=6\Rightarrow -\frac{9*6}{10}=-5,4$

$3)\frac{6+3d}{c}-\frac{4d^{2}+6d}{cd}=\frac{6d+3d^{2}-4d^{2}-6d}{cd} =-\frac{d^{2} }{cd} =-\frac{d}{c}\\\\c=2;d=1,2\Rightarrow -\frac{1,2}{2}=-0,6\\\\4)\frac{7-2b}{ab}:\frac{28-8b}{a^{2}}=\frac{7-2b}{ab}*\frac{a^{2} }{4(7-2b)}=\frac{a}{4b}\\\\a=38;b=5\Rightarrow \frac{38}{4*5} =1,9$

$5)\frac{b^{2}-ab}{2a}*\frac{4a}{-a+b}=\frac{b(b-a)}{2a}*\frac{4a}{b-a}=2b\\\\b=1,6\Rightarrow 2*1,6=3,2$