Quartic equation root calculator

For example, input：a=3, b=6, c=-123, d=-126 e=1080
ax4 + bx3 + cx2 + dx + e = 0
x4 + x³ + x² + x + e
Results:
x1: +   i
x2: +   i
x3: +   i
x4: +   i

A quartic equation is a polynomial equation whose highest degree of unknown number does not exceed four.