Question

$x + y = 20 \\ xy = 19$
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Answer 1

Resposta:

$x + y = 20 \\ xy = 19 \\ x = 20 - y \\ (20 - y)y = 19 \\ - {y}^{2} + 20y- 19 = 0 \\ delta = ( 20)^{2} - 4 \times - 1 \times - 19 = \\ 400 - 76 = 324 \\ x1 = \frac{ - 20 - 18}{ - 2} = \frac{ - 38}{ - 2} = 19 \\ x2 = \frac{ - 20 + 18}{ - 2} = \frac{ - 2}{ - 2} = 1$

x'= 19

x" = 1