Question

2x ao quadrado mais x menos 1 igual a zero

Answer 1

$2x^2+x-1=0\\ \Delta = 1^2-4*2*-1 = 9 \\\\ x = \frac{-1+- \sqrt{9} }{2*2}\\\\ x_1= \frac{-1+3}{4} = \frac{2}{4} = \frac{1}{2}\\\\ x_2=\frac{-1-3}{4} = -2$

Answer 2

2x²+x-1=0
a=2
b=1
c=-1
∆=1²-4×2×-1
∆=1+8
∆=9
x=-1±√9÷2×2
x=-1±3÷4
x¹=-1+3÷4=2÷4=0,5
x²=-1-3÷4=-4÷4=-1
S=0,5;-1