>>478
25/L2 = b,
L7/100 = c,
とおくと
a = L9 * c * {L12 - (1000/L5)*b} + L9 * (1-c) * {L12 - (1000/L5)},
は (1000/L5) について一次方程式
L5 = 1000(bc-c+1)/{L12 - (a/L9)},