Question

Seja (x-y)elevado a 2 - (x+y)elevado a 2 = -80. Determine x e y

Answer 1

x2 -2xy +y2 - x2 + 2xy +y2 =-80
2y2=-80
y2=-80/2
y2=-40

Answer 2

vamos lá...

$(x-y)^2-(x+y)^2=-80 \\ \\ x^2-2xy+y^2-(x^2+2xy+y^2)=-80 \\ \\ x^2-2xy+y^2-x^2-2xy-y^2=-80 \\ \\ \not x^2-\not x^2+\not y^2-\not y^2-2xy-2xy=-80 \\ \\ -4xy=-80 \\ \\ 4xy=80 \\ \\ xy=80\div4 \\ \\ xy=20$