Question

х? -у? х?—2xy+y?
5х2
25х
при х=2, y=1.​

Answer 1

$\frac{ {x}^{2} - {y}^{2} }{5 {x}^{2} } \div \frac{ {x}^{2} - 2xy + {y}^{2} }{25x} = \frac{(x - y)(x + y) \times 25x}{5 {x}^{2}(x - y) {}^{2} } = \frac{5(x + y) }{x(x - y)} = \frac{5(2 + 1)}{2(2 - 1)} = \frac{5 \times 3}{2 \times 1} = \frac{15}{2} = 7.5$