Slope intercept form is y = mx + b
So if you start with 9x - 7y = -7, the first thing you need to do is move the 9x to the other side of the equation by subtracting it from both sides.
9x - 7y = -7
-9x -9x
Now you have -7y = -9x -7
For the equation to be in slope intercept form now you should divide every term by the number in front of your y. In this case divide every term by -7
-7y = -9x -7
-7 -7 -7
That leaves you with: y = 9x/7 + 1
