已知x+y=3,xy=-2.求代数式(3xy+10y)+[4x-2(3xy+2y-x)]
谢谢啦、
(3XY+10Y)+[4X-2(3XY+2Y-X)]
=3XY+10Y+4X-6XY-4Y+2X
=-3XY+6X+6Y
=-3XY+6(X+Y)
=-3*2+6*3
=12