Question

Cálculo do sistema de equação x²-2y²=14 x+y=5

Answer 1

x²-2y²=14
x+y=5
x=5-y

(5-y)²-2y²=14
(5-y)(5-y)-2y²=14
25-5y-5y+y²-2y²=14
25-10y+y²=14
y²-10y+25-14=0
y²-10y+11=0
a=1 b=-10 c=11
∆=-10²-4•1•11
∆=100-44
∆=56
y=-(-10)±√56/2•1
y=10±√56/2