Система: х+у=5 2х-у²=7

Question

Система: х+у=5
2х-у²=7

Answer 1

Х = 5 - y
2 * ( 5 - y ) - y^2 = 7
10 - 2y - y^2 = 7
Y^2 + 2y - 3 = 0
D = 4 + 12 = 16 ; кв.корень 16 = 4
Y1 = ( - 2 + 4 ) : 2 = 1
Y2 = ( - 2 - 4 ) : 2 = - 3
X = 5 - y
X1 = 5 - 1 = 4
X2 = 5 + 3 = 8
Ответ ( 4 ; 1 ) ; ( 8 ; - 3 )