1.(-2x^4y^2z^3)*(-3x^2y^2z^4)= 6x^6y^4z^7
2.(5x^3-2x^2+3x+4)-(3x^3-5x^2+3)= 2x^3+3x^2+1
3.(√3+3√2)(2√3-√2)=5√6
如果认为讲解不够清楚,