Ответ:
1)
{x = 13-2y
{(13-2y)*y = 15
13y - 2y^2 - 15 = 0 / :(-1)
2y^2 - 13y + 15 = 0
D = 169 - 120 = 49
√D = 7
y1= (13 - 7)/4 = 6/4 = 3/2 = 1,5
y2= (13+7)/4 = 20/4 = 5
x1= 13 - 2y1 = 13 - 3 = 10
x2= 13 - 2y2 = 13 - 10 = 3
2)
{x = 2+2y
{(2+2y)*y=12
2y^2 + 2y - 12 = 0
D = 4 + 96 = 100
√D = 10
y1= (-2-10)/4 = -12/4 = -3
y2= (-2+10)/4 = 8/4 = 2
x1= 2 + 2y1 = 2 + 2(-3) = 2 - 6 = -4
x2= 2+2y2 = 2 + 2*2 = 6