16x⁴ - 121x² = 0
x²(16x²) - x²(121) = 0
x²(16x² - 121) = 0
x²(16x² + 44x - 44x - 121) = 0
x²(4x(4x) + 4x(11) - 11(4x) - 11(11)) = 0
x²(4x(4x + 11) - 11(4x + 11)) = 0
x²(4x - 11)(4x + 11) = 0
x² = 0 or 4x - 11 = 0 or 4x + 11 = 0
√(x²) = √(0) + 11 + 11 - 11 - 11
x = 0 or 4x = 11 or 4x = -11
4 4 4 4
x = 2³/₄ or x = -2³/₄
Solution Set: {0, ±2³/₄}