Ok so first you'll need the slope-intercept formula known as y=mx+b. This is where m= slope and b = y-intercept
Basically you would look at the equation and see where the number is in relation to the formula.
y=40x+30
y=mx+b
You can see that 40 = m (slope) and 30 = b (y-intercept)
That's finding the slope and y-intercept. To find points on the line, all you have to do is put a number in for the x and solve it to get the y. Then you will have an (x,y) coordinate.
Example:
x=1
y=40x+30
y=40(1)+30 (40 times 1 = 40)
y=40+30
y=70
So, if you used 1, your coordinate point would be at (1,70)