先化简,再求值:(8x-3y)-(4x+3y-2)+2z其中x=0.5,y=-1,z=2
问题描述:
先化简,再求值:(8x-3y)-(4x+3y-2)+2z其中x=0.5,y=-1,z=2
顺便把过程写上.要是对的.
答
(8x-3y)-(4x+3y-2)+2z
=8x-3y-4x-3y+2+2z
=4x-6y+2z+2
=2(2x-3y-z+1)
代入x=0.5,y=-1,z=2
=2(2*(0.5)-3*(-1)-2+1)
=2(1+3-2+1)
=6