Question

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

Answer 1

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