解:解方程,此方程的解为x = 25 1500x + 2100 × (50 - x)= 90000 1500x + 105000 - 2100x = 90000 -600x = 90000 - 105000 -600x = -15000 x = (-15000)÷ (-600) x = (-15000)× (-1/600) ∴x = 25 答:此方程的解为x = 25