The equation of a line is typically written as:

y=mx+b, where m is the slope and b is the y-intercept

The slope m= (y2-y1)/(x2-x1) where (x1, y1) and (x2, y2) are points of the line.

In our case 

x1 = 2, y1 = -4

x2 = 1, y2 = 0

We plug the values and find m:

m = (0 - (-4))/(1 - 2)

m = 4/(-1)

m = -4

Next we need to find b.

So far we have the following equation:

y = -4x + b

Since the line is passing trough (1, 0) we can plug x = 1 and y = 0 to find b:

0 = -4*1 + b

b - 4 = 0

b = 4

The equation of the line is:

y = -4x + 4