1. The slope-intercept form is y=mx+b. It tells you the slope (m) and the y-intercept (b). So, for example, if you had y=3x+5 then your slope is 3 and your y-intercept is 5.
2. If it is a function the x values or domain, cannot repeat. In an input/output table, that would be the input side so if any of those values repeat it is not a function.
3. y=x+4 I got that by finding the slope (
) and we know that the y-intercept is (0,4) so we can plug in y=1x+4 and you can drop the 1.
Hope all this helps