Question

{x²-2y²=-14
{x+y=1

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Answer 1

{x^2 - 2y^2 = - 14
{x + y = 1 => x = 1 - y

x^2 - 2y^2 = - 14
(1 - y)^2 - 2y^2 = - 14
(1)^2 + 2 (1)(y) - (y)^2 - 2y^2 = - 14
1 + 2y - y^2 - 2y^2 = -14
-3y^2 + 2y + 1 + 14 = 0
-3y^2 + 2y + 15 = 0..(-1)
3y^2 - 2y - 15 = 0
a=3...b=-2...c= - 15

formula delta

D = b^2 - 4 a c
D = (-2)/2 - 4 (3) (-15)
D = 4 - 12 (-15)
D = 4 + 180
D = 184

formula de braskara

x = - b + , - \/D
......________
.............2 a

x = - (-2) + , - \/184
......___________
...............2 (3)

x = 2 + , - 13,56
......_________
................6

x' = 2 + 13,56
.....________
..............6

x'= 15,56
......____
..........6

x' = 2,59

x" = 2 - 13,56
......._______
.............6

x" = - 11,56
.......______
..............6

x" = - 1,9266

x* 1,93