9x^2-4y^2/20y^2-60xy+45x^3 и найти ее значение при x = 2/3, y = 0,75

9x² - 4y²/20y² - 60xy + 45x³, x = 2/3, y = 0,75 = 3/4,

9x² - 4y²/20y² - 60xy + 45x³ =

9x² - 1 / 5 - 60xy + 45x³ =

9 * (2/3) ² - 1/5 - 60 * (2/3 * 3/4) + 45 * (2/3) ³ =

9 * 4/9 - 1/5 - 60 * (6/12) + 45 * 8/27 =

4 - 1/5 - 30 + 5 * 8/3 =

4 - 1/5 - 30 + 40/3 =

- 26 - 1/5 + 40/3 =

( - 26 * 15 - 3 + 40 * 5) / (3 * 5) =

( - 390 - 3 + 200) / (3 * 5) =

( - 193) / 15 =

- 193/15.

Ответ: - 193/15.