Question

-20=-x-x2 forma geral

Answer 1

2X=20+2
2X=22
X=22/2
X=11

Answer 2

x+x²-20=0
∆=(1)²-4(1)(-20)
∆=1+80
∆=81
x=-(1)±√81 / 2.1
x=-1±9 / 2
x'=-1+9 /2
x'=8 / 2
x'=4
x"=-1-9 / 2
x"=-10 / 2
x"=-5