ok you find the slope by setting y alone you do this by subtracting 7 from both sides when you do you will end with -3y=9x-7 now divide 9x-7 by -3 to leave the y by itself this will give you y=-9/3x+7/3. now simplify the -9/3 and get -3. the final equation would be y=-3x+7/3 teh slope is the number next to the x, so you r slope would be -3
Hope this helped