Respostas

  • Usuário do Brainly
2014-07-29T20:09:40-03:00
A)
2x=15-x²

x²+2x-15=0

Δ=4+60
Δ=64
√Δ=√64=8

x'= \frac{-2+8}{2} = \frac{6}{2}=3

x"= \frac{-2-8}{2} =- \frac{10}{2} =-5

S={-5,3}

b)
x²+3x-6=-8
x²+3x-6+8=0
x²+3x+2=0
Δ=9-8
Δ=1
√Δ=√1=1

x'= \frac{-3+1}{2} =- \frac{2}{2} =-1

x"= \frac{-3-1}{2} =- \frac{4}{2} =-2

S={-2,-1}