For this case we have that by definition, the equation of a line of the slope-intersection form is given by:

Where:
m: It is the slope of the line
b: It is the cut point with the y axis
By definition, if two lines are perpendicular then the product of their slopes is -1.
If we have: 

Thus, the equation is of the form:

We substitute the point:

Finally, the equation is:

Answer:

4x - 2x + 8 = 6(x + 4) Given
(4x - 2x) + 8 = 6(x + 4)
2x + 8 = 6(x + 4) Combine like terms
2x + 8 = (6)(x) + (6)(4)
2x + 8 = 6x + 24 Distributive Property
2x - 6x + 8 = 6x - 6x + 24
-4x + 8 = 24 Subtraction Property of Equality
-4x + 8 - 8 = 24 - 8
-4x = 16 Subtraction Property of Equality
-4x : (-4) = 16 : (-4)
x = -4 Division Property of Equality
47-12 1/3= 34 2/3 so the answer is 34 2/3 yards of fabric
So first you divide by 2 from y so it would equal y=4x+2 and the slope is 4 over 1 and the yintercept is (0,2)