Question

resolva o sistema 2x + y = -3
8x^2 - y^2 = -17

Answer 1

Oi 

2x+y=-3
8x²-y²=-17

2x+y=-3
y=-3-2x

8.x²-y²=-17
8.x²-(3-2x)²=-17
8x²-(9-2.3.-2x+4x²)=-17
8x²-( 9+12x+4x²=-17
8x²-12x-4x²=-17
4x²-12x+8=0 ( dividindo todos os termos por 4)

1x²-3x+2=0

Δ=b²-4.a.c
a=1
b=-3
c=2

Δ= -3²-4.1.2
Δ=9-8
Δ=1

x=$\frac{-b+- \sqrt{delta} }{2.a}$

x'=[tex] \frac+3+1}{2} = 4/2=+2

x"=[tex] \frac{3-1}{2} = 1

Para x'=+2
y=-3-2x
y=-3-2.+2
y=-3-4
y=-7

Para x"
x"=+1
y=-3-2x
y=-3-2.+1
y=-3 -2
y=-5

S( x'=+2,y'=-7+,x"=+1,y"=-5)



Bons estudos!!!