x {-2; 2}
Объяснение:
x⁴ - 3x² - 4 = 0
x² = y
y² - 3y - 4 = 0
Δ = b² - 4ac = 3² - 4×1×(-4) = 9 + 16 = 25
y1 = (- b - √Δ)/2a = (3 - 5)/2 = -2/2 = -1 ∉
y2 = ( - b + √Δ)/2a = (3 + 5)/2 = 8/2 = 4
x² = 4
x = √4
x = ± 2
