Question

Известно что x + y=7 xy=6 найдите значение выражения x^2y+ xy^2

Answer 1

$x + y = 7 \ xy = 6 \ = = = = = = = \ y = 7 - x \ x(7 - x) = 6 \ 7x - {x}^{2} = 6 \ {x}^{2} - 7x + 6 = 0 \ x = frac{7 + sqrt{49 - 24} }{2} = frac{7 + 5}{2} = 6 \ x = frac{7 - sqrt{49 - 24} }{2} = frac{7 - 5}{2} = 1 \ = = = = = = = = \ {x}^{2} y + x {y}^{2} = 42$