(а^2+2аb+b^2)-(a^2-2ab+b^2)=
=a^2+2ab+b^2-a^2+2ab-b^2=2ab+2ab=4ab
Сделаем замену :
Ответ : (- 2 ; - 4) , (2 ; 4)
(2/7 + 7/2)/ 1 - 2/7 = 53/14 / 5/7 = 53/14 * 7/5 = 53/10 = 5.3
<span>x+3y=0
x^2+y^2-2xy=9
--------------
(x-y)^2=9
x-y=3
x+3y=0
x+3y-x+y=0-3
4y=-3
y=-3/4
x=9/4
x-y=-3
x+3y=0
x+3y-x+y=0-(-3)
4y=3
y=3/4
x=-9/4</span>