Question

x-20x+64=0
a=1
b=20
c=64

Answer 1

Vamos lá usando :

-b±√b²-4.a.c/2a

20±√400-4.1.64/2

20±√144/2
20±12/2

x'= 20+12/2= 16
x"= 20-12/2=4

Bons estudos :)