Slope is “rise over run” or “up over across.” The points you are given are (x,y), which means “across, then up”. So you just need to subtract the second y from the first, and the second x from the first.
In the first problem, you have (0,0) and (6,7), or think of them as (x1, y1) and (x2, y2). You just need to find the two differences and divide (slope can be negative).
For problem #1, it is (7-0)/(6-0), which is the same as 7/6 because any number minus 0 is itself.
Use this method for the others and you will have your answers.