Question

resolva as equaçoes a) 2x^2-1=1-x-x^2​

Answer 1

Resposta:

2x² -1 = 1 -x -x²

2x² + x² +x -1 -1=0

3x² + x - 2 = 0

a=3

b=1

c=-2

Δ=b² -4ac

Δ=1²-4(3)(-2)

Δ=1+24

Δ=25

$x={-b\pm\sqrt{\Delta} \over2a}={-1\pm\sqrt{25} \over2(3)}={-1\pm5\over6}\\ \\ x_1={-1-5\over6}=-{6\over6}=-1\\ \\ x_2={-1+5\over6}={4\over6}={2\over3}\\ \\ S=\{-1,{2\over3}\}$