求未知数X'v-u'N;D1~1i-h2z
2X+2.7=24.7'v-u'N;D1~1i-h2z
算式：提示+T.W.H*y)W2f;g,Z+f)s1g5A:q.e1m8L'v-u'N;D1~1i-h2z
X=:P8Z0N4c-v9M-B1u7G'v-u'N;D1~1i-h2z