先化简,再求值:3+[3(x+2y)-(x-1)]其中x=﹣1,y=1/3

问题描述:

先化简,再求值:3+[3(x+2y)-(x-1)]其中x=﹣1,y=1/3


3+[3(x+2y)-(x-1)]
=3+(3X+6Y-X+1)
=3+2X+6Y+1
=2X+6Y+4
=2*(-1)+6*1/3+4
=-2+2+4
=4