Question

Como se resolve
{2x+y=6
{xy=-20

Answer 1

Oi Paula

2x + y = 6
xy = -20

y = 6 - 2x

x*(6 - 2x) = -20

x*(2x - 6) = 20

2x² - 6x - 20 = 0

x² - 3x - 10 = 0

delta
d² = 9 + 40 = 49
d = 7

x1 = (3 + 7)/2 = 10/2 = 5 , y1 = 6 - 2x1 = 6 - 10 = -4
x2 = (3 - 7)/2 = -4/2 = -2 , y2 = 6 - 2x2 = 6 + 4 = 10