So since you know that this is a line you can use the slope intercept form which is y=mx+b. M being the slope and B being the y intercept. So for 5a. It is asking for the equation so you just plug in the numbers into y=mx+b.
y=5x-2
For 5b all you have to do is plug in 0 for y in the equation above.
So it will be 0=5x-2. So you simplify it.
Subtract 2 to both sides and you get -2=5x
THen divide by 5 on both sides to isolate the x and so you will get -2/5 =x.
So the answer would be the value of x when y is 0 is -2/5
I really hope that this helped you in some way. If you have any questions feel free to ask me. Have a great day :)