6x-2(1-x)=x+2-6
6x-2+2x=x-4
7x=-2
X=-
2
7 ;
(2)原式=10a 2-14ab+18b 2-42a 2+6ab-9b 2
=-32a 2-8ab+9b 2
当a=
3
4 ,b=-
2
3 时,原式=-32× (
3
16 ) 2 -8×
3
4 ÷(-
2
3 ) =-18+4+4=-10.
6x-2(1-x)=x+2-6
6x-2+2x=x-4
7x=-2
X=-
2
7 ;
(2)原式=10a 2-14ab+18b 2-42a 2+6ab-9b 2
=-32a 2-8ab+9b 2
当a=
3
4 ,b=-
2
3 时,原式=-32× (
3
16 ) 2 -8×
3
4 ÷(-
2
3 ) =-18+4+4=-10.