(3x-2y+3xy)-(x-4y-2xy),其中x+y=3 xy=-2 化简求值
问题描述:
(3x-2y+3xy)-(x-4y-2xy),其中x+y=3 xy=-2 化简求值
答
(3x-2y+3xy)-(x-4y-2xy) = 3x - 2y + 3xy - x + 4y + 2xy = 2x + 2y + 5xy = 2(x+y) + 5xy = 2 * 3 + 5 * (-2) = 6 - 10 = -4