Question

Упростите выражение !

Answer 1

$\displaystyle \frac{x^2-y^2}{2xy} :\frac{3x-3y}{2y}= \frac{(x-y)(x+y)}{2xy} \cdot \frac{2y}{3(x-y)}=\frac{x+y}{3x}$

при х =25; у=-4

$\displaystyle \frac{x+y}{3x} =\frac{25+(-4)}{3 \cdot 25} =\frac{25-4}{3 \cdot 25} =\frac{21}{3 \cdot 25} =\frac{7}{25}$

Answer 2

$\frac{ {x}^{2} - {y}^{2} }{2xy} \div \frac{3x - 3y}{2y} = \\ = \frac{ {x}^{2} - {y}^{2} }{2xy} \times \frac{2y}{3(x - y)} = \\ = \frac{(x - y)(x + y)}{2xy} \times \frac{2y}{3(x - y)} = \frac{x + y}{3x} = \\ = \frac{25 - 4}{3 \times 25} = \frac{21}{75} = \frac{7}{25} = 0.28$