﹙x²+px+q﹚﹙x²-3x+q﹚=x^4-3x^3+qx^2+px^3-3px^2+pqx+qx^2-3qx+pq=x^4+(p-3)x^3+(2q-3p)x^2+(pq-3q)x+pq因为乘积中不含x²项和x³项所以p-3=0,2q-3p=0p=3 ,q=9/2