Can someone help me with this

Answer:
[tex]y = - 2x[/tex]
Step-by-step explanation:
For question 3, the only one, fully visible, read below the explanation.
First of all, find the slope, or gradient, or m.
Should be easy as
[tex] \frac{rise}{run} = \frac{2}{ - 1} = - 2[/tex]
Then, see where the line intersects the y-axis. You should note it is at x=0, meaning the y-intercept is 0.
Knowing this:
[tex]y = mx + c \\ y = - 2x + 0 \\ y = - 2x[/tex]
And there you go.