回答:
v = 21
説明:
1 / v +(3v + 12)/(v ^ 2-5v)=(7v-56)/(v ^ 2-5v)
1 / v +(3v + 12)/(v ^ 2-5v) - (7v-56)/(v ^ 2-5v)= 0
一般的な分母は v ^ 2-5v = v(v-5)
(v-5 + 3v + 12-(7v-56))/(v ^ 2-5v)= 0
(v-5 + 3v + 12-7v + 56)/(v ^ 2-5v)= 0
(v + 3v-7v-5 + 12 + 56)/(v ^ 2-5v)= 0
( - 3v + 63)/(v ^ 2-5v)= 0
-3v + 63 = 0
-3v = -63
v =( - 63)/( - 3)
v = 21