Question Number 148756 by mathdanisur last updated on 30/Jul/21

{ ((x^2 + xy + x + y = −2)),((y^2 + xy + x + y = 1)) :} ⇒ 3x + y = ?

Answered by mindispower last updated on 30/Jul/21

(1)+(2)⇒(x+y)^2 +2(x+y)+1=0 ⇒(1+(x+y))^2 =0 ⇒x+y=−1 (1)−(2)⇒x^2 −y^2 =−3 (x−y)(x+y)=−3 ⇒x−y=3 2(x+y)+x−y=3x+y=2(−1)+3=1

Commented bymathdanisur last updated on 31/Jul/21

Thank You Ser