Question

будь ласка Спростити вираз
Знайти його значення при x=0,25;y=-0,47

Answer 1

$\displaystyle\bf\\1)\\\\\frac{x+y}{x}-\frac{2x}{x-y} =\frac{(x+y)\cdot(x-y)-2x\cdot x}{x\cdot(x-y)}=\\\\\\=\frac{x^{2} -y^{2} -2x^{2} }{x\cdot(x-y)} =\frac{-x^{2} -y^{2} }{x\cdot(x-y)} =-\frac{x^{2}+y^{2} }{x\cdot(x-y)} \\\\2)\\\\-\frac{x^{2}+y^{2} }{x\cdot(x-y)} \cdot\frac{y-x}{x^{2} +y^{2} } =\frac{x^{2}+y^{2} }{x\cdot(y-x)} \cdot\frac{y-x}{x^{2} +y^{2} } =\frac{1}{x} \\\\\\x=0,25\\\\\\\frac{1}{x} =\frac{1}{0,25} =\frac{100}{25} =4\\\\\\Otvet \ : \ 4$