Question

x elevado a 4 menos 20 x elevado a 2 mais 64 igual a 0

Answer 1

x⁴-20x²+64=0
x⁴=y²
x²=y
y²-20y+64=0
∆=b²-4ac
∆=(-20)²-4.1.64
∆=400-256
∆=144
y=-b±√∆/2a
y=-(-20)-12/2.1
y=20-12/2
y=8/2
y=4
y=-(-20)+12/2.1
y=20+12/2
y=32/2
y=16
S={+4, -4, +16, -16}