Question

sistemas 2xy = -18
x+y=8
qual o valor de 2x ?

Answer 1

2xy =-18

y = -18/x

-18/x + x = 8

-18 + x^2 = 8x

x^2 -8x - 18 = 0

x^2 -8x + 16 = 34

(x - 4)^2 = 34

x - 4 = ±√34

x = 4 ± √34

2x = 8 + 2√34 ou 8 - 2√34