Answer:
3
Step-by-step explanation:
We can find the slope of the given line in this two way:
1) the faster is calculate -a/b where a is the number the multiply x and b is the number the multiply y. In this case we have -1/3
2) the second method is rewrite the equation in slope intercept form and find the therm that multiply x
3y = -x-15
y = -1/3x - 5
Also in this case we have -1/3
Two perpendicular lines have the the product of the their slope that is -1
So the slope that we are finding is 3
In fact = 3 x -1/3 = -1
