已知多项式A=3x^2-5xy,B=-3xy-x^2,C=8x^2-5xy,求2A-5B+2C的值

问题描述:

已知多项式A=3x^2-5xy,B=-3xy-x^2,C=8x^2-5xy,求2A-5B+2C的值
数度啊

2A-5B+2C
=2(3x^2-5xy)-5(-3xy-x^2)+2(8x^2-5xy)
=6x²-10xy+15xy+5x²+16x²-10xy
=27x²-5xy在问你个问题