Need help step by step

Y = mx + b

8x - 4y - 9 = 0

first you move the nine to the other side of the equal sign (add nine to both sides)

8x - 4y = 9

then you need to also move your 8x over to the other side as well (remember we are trying to get y by itself!)

- 4y = -8x + 9

then we are going to divide -4 to both sides

and you get

y = 2x - 9/4

we can then identify the slope as 2

so B. 2 would be your answer

hope this helped