Question

Cum se rezolva sistemul x+3xy+y= -5
xy= -2 reeeepede

Answer 1

Răspuns:

(x,y)apartine{(2, -1);(-1, 2)}

Explicație pas cu pas:

x + 3xy + y = -5

x + 3 * -2 + y = - 5

x + (-6) + y = - 5

x + y = 1

x = 1 - y

(1-y)* y = -2

y - y * y = -2

- y* y + y + 2 = 0

y la 2 - y - 2 = 0

y la 2 + y - 2y - 2 = 0

y(y + 1) - 2(y + 1) = 0

(y + 1)(y-2) = 0 => y + 1 = 0 => y = -1 => x = 2

                           y - 2 = 0 => y = 2 => x = -1