Answer :
0 becuase the slope of a line is the amount of one y to another and both y's are 9 so there is no slope.
Steps:
1. Do the slope formula
Y2-Y1
--------
X2-X1
2.
9-9
------
9- (-1)
3. 9-9=0
9 + 1=10
4. 0/10 = 0
5. Your answer is 0
1. Do the slope formula
Y2-Y1
--------
X2-X1
2.
9-9
------
9- (-1)
3. 9-9=0
9 + 1=10
4. 0/10 = 0
5. Your answer is 0