A)7xy(4x²y - 12x + 15y - 18xy² - 19x²y² - 13x - 12y² - 19xy - 18y (x = ½ , y = - ⅔)B) 12a(7ab - 18a² - 2ab² - 3b - 12a²b² - 18ab² + 14ab - 19b²(a = 3 , b = ¾)C)7mn(8m² - 12mn + 10m²n² - 15mn - 16n² + ?
A)7xy(4x²y - 12x + 15y - 18xy² - 19x²y² - 13x - 12y² - 19xy - 18y (x = ½ , y = - ⅔) B) 12a(7ab - 18a² - 2ab² - 3b - 12a²b² - 18ab² + 14ab - 19b² (a = 3 , b = ¾) C)7mn(8m² - 12mn + 10m²n² - 15mn - 16n² + 18m² - 13n² (m = - 3 / 5 , n = 2). Porfa ayudenme.