Question

sistema de equacao
x² + y² = 2
x - 2y = 3

Answer 1

x - 2y = 3
x = 3 + 2y ******

x² + y²  = 2
(3 + 2y)² + y²  = 2
[ (3² + 2 * 3 * 2y + (2y)² ] + y²  = 2
9 + 12y + 4y² + y² - 2 = 0
5y² + 12y + 7 = 0
delta = 144 - 140 = 4 ou +-V4 = +-2 ***
y = ( -12 +- 2)/10
y1 = -10/10 = -1 *****
y2 = -14/10 = - 7/5 ****