Question

X elevado a 4-2X elevado a 2-15=0

Answer 1

x⁴ - 2x² - 15 = 0

y² - 2y - 15 = 0

a = 1, b = - 2, c = - 15

Δ = b² - 4 . a . c
Δ = (-2)² - 4 . 1 . (-16)
Δ = 4 + 64
Δ = 68

$x = \dfrac{-b \pm \sqrt{\Delta} }{2a}\\\\\\x = \dfrac{2 \pm \sqrt{68} }{2}$

$x = \dfrac{2 \pm \sqrt{68} }{2}\\\\\\x'= \dfrac{ \sqrt{68} }{2} \\\\\\x''= \dfrac{- \sqrt{68} }{2}$



Forte abraço!