方程除以四次方系數7，得 x?+5/7x?+3/7x?+2/7x+11/7=0
根據費拉裏公式，需要求解三次方程 8y?-12/7y?-596/49y+621/343=0
按盛金公式得其中壹解為 y= -1.204273
按費拉裏公式，原方程可拆分為兩個方程
2x?+(0.71429+3.29215i)x+(-2.40855+0.69615i)=0
2x?+(0.71429-3.29215i)x+(-2.40855-0.69615i)=0
求解這兩個方程，得
X1= -0.926954442081354 - 0.786872864226335i
X2= 0.569811584938496 - 0.859203272412195i
X3= -0.926954442081353 + 0.786872864226334i
X4= 0.569811584938497 + 0.859203272412196i