Does every line have a slope and a y intercept?

no

Step-by-step explanation:

because the line can be 0

see below

Step-by-step explanation:

Not every line has a y intercept because vertical lines (lines that go up and down) do not intersect the y axis

Does every line have slope? It depends on how you define slope

Vertical lines have a slope that is undefined. So they have a slope that is undefined. When you are asked what the slope of a vertical line is, you answer undefined