Question

equação 2 grau
5x2 - 20 = 0

Answer 1

∆=0+5.4.20=400
x1=0+20/10=2
x2=0-20/10=-2

Answer 2

5x²-20=0
5x²=20
x²=20/5
x²=4
x=√4
x=±2
x'=2
x''=-2

S(-2 , 2)