9x-6x=7+14

3x=21

x=7

8x+3-10x-6=9

8x-10x=9-3+6

-2x=12

x=-6

9х-7=6х+14

9х-6х=14+7

3х=21

х=7

(8х+3)-(10х+6)=9

8х+3-10х-6=9

8х-10х=9-3+6

-2х=12

х=-6