Hi there!
2x - 4y = 9
Begin by isolating the y variable by moving 2x to the right-hand side of the equation. (Subtract 2x from both sides):
2x - 2x - 4y = 9 - 2x
-4y = 9 - 2x
Further isolate by dividing both sides by -4:
-4y / (-4) = (9 - 2x) / (-4)
y = -9/4 - 2x/(-4)
Simplify further:
y = -9/4 + 1/2x
y = 1/2x - 9/4
The "b" value is the y-intercept, therefore:
x = 0 at y = -9/4