Do a y=mx+b equation

y=-2x

Step-by-step explanation:

The y-intercept is 0 so b is 0

and it is going down   2 right 1 so it is -2/1  -2/1 =-2 so it is y= -2x

y = -2x + 0

Step-by-step explanation:

y = mx + c

m = gradient and c = y intercept ( the point where the line intercepts the y axis)

Firstly, we can tell the gradient is negative because it has a negative slope (sorta like down a hill) where as x increases y decreases.

To calculate the gradient you use the equation y/x

Pick anywhere on you graph and measure. I have taken from (0,0) to (0,-4) for y and (0,-4) to (2,-4) for x.

Next subtract them (0,-4) - (0,0) = 0,-4. Then take that - 4 for y

Next subtract for them for x (0,-4) - (2,-4) = 0- 2 and -4 -(-4)

                                                                    = -2 and -4 + 4 = 0

                                                                    = -2

So y = -4 and x = -2

y/x = 4/2 = 2

Because we know our gradient is negative add a minus and we get our gradient as -2

For y intercept simply find where the line crosses through the y axis, which in this question happens to be 0

answer = -2x + 0