Question

x+y=-9 ; x2( patrat) + y2= 36
aflati : x-y.

Answer 1

$(x+y)^{2} = x^{2} +2xy+ y^{2} =81 \\ 2xy=81-36 \\ 2xy=45 \\ x^{2} -2xy+ y^{2}=36-45 \\ (x-y)^{2}=-9\ \textless \ 0$
imposibil