(72x31y55z25x45y)+(71x4y21z91x)+(1x2y32z44x41y)=(a)
(a)-(xyz)=(c)
(41x1y34z43x52y)+(33x93y21z91x)=(b)
(b)-(xyz)=(d)
(c)+(d)=(e)

eの値を求めよ

解き方だけでもおながいします